# description
A record of a request for diagnostic investigations, treatments, or operations to be performed.

# copyright
Copyright © 2019 HL7 UK    Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at    http://www.apache.org/licenses/LICENSE-2.0    Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the specific language governing permissions and limitations under the License.    HL7® FHIR® standard Copyright © 2011+ HL7    The HL7® FHIR® standard is used under the FHIR license. You may obtain a copy of the FHIR license at    https://www.hl7.org/fhir/license.html

# snapshot.element[].short
A request for a procedure or diagnostic to be performed

# snapshot.element[].definition
A record of a request for diagnostic investigations, treatments, or operations to be performed.

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL NOT contain nested Resources

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL NOT contain any narrative

# snapshot.element[].constraint[].human
If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated

# snapshot.element[].constraint[].human
If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource

# snapshot.element[].definition
The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

# snapshot.element[].comment
The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content may not always be associated with version changes to the resource.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The version specific identifier, as it appears in the version portion of the URL. This values changes when the resource is created, updated, or deleted.

# snapshot.element[].comment
The server assigns this value, and ignores what the client specifies, except in the case that the server is imposing version integrity on updates/deletes.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
When the resource last changed - e.g. when the version changed.

# snapshot.element[].comment
This value is always populated except when the resource is first being created. The server / resource manager sets this value; what a client provides is irrelevant.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Profiles this resource claims to conform to

# snapshot.element[].definition
A list of profiles (references to [StructureDefinition](structuredefinition.html#) resources) that this resource claims to conform to. The URL is a reference to [StructureDefinition.url]().

# snapshot.element[].comment
It is up to the server and/or other infrastructure of policy to determine whether/how these claims are verified and/or updated over time.  The list of profile URLs is a set.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Security Labels applied to this resource

# snapshot.element[].definition
Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure.

# snapshot.element[].comment
The security labels can be updated without changing the stated version of the resource  The list of security labels is a set. Uniqueness is based the system/code, and version and display are ignored.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Security Labels from the Healthcare Privacy and Security Classification System.

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].definition
Tags applied to this resource. Tags are intended to be used to identify and relate resources to process and workflow, and applications are not required to consider the tags when interpreting the meaning of a resource.

# snapshot.element[].comment
The tags can be updated without changing the stated version of the resource.  The list of tags is a set. Uniqueness is based the system/code, and version and display are ignored.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Codes that represent various types of tags, commonly workflow-related; e.g. "Needs review by Dr. Jones"

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
A set of rules under which this content was created

# snapshot.element[].definition
A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

# snapshot.element[].comment
Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element.   This element is labelled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The base language in which the resource is written.

# snapshot.element[].comment
Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies  to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource  Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Text summary of the resource, for human interpretation

# snapshot.element[].definition
A human-readable narrative that contains a summary of the resource, and may be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

# snapshot.element[].comment
Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied).  This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded in formation is added later.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

# snapshot.element[].comment
This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again.

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the resource. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
Identifiers assigned to this order instance by the orderer and/or the receiver and/or order fulfiller.

# snapshot.element[].comment
The identifier.type element is used to distinguish between the identifiers assigned by the orderer (known as the 'Placer' in HL7 v2) and the producer of the observations in response to the order (known as the 'Filler' in HL7 v2).  For further discussion and examples see the resource notes section below.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
usual | official | temp | secondary (If known)

# snapshot.element[].comment
This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one. Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

# snapshot.element[].requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Identifies the purpose for this identifier, if known .

# snapshot.element[].definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].comment
This element deals only with general categories of identifiers.  It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage.   Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

# snapshot.element[].requirements
Allows users to make use of identifiers when the identifier system is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].definition
Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

# snapshot.element[].requirements
There are many sets  of identifiers.  To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

# snapshot.element[].example[].valueUri
http://www.acme.com/identifiers/patient or urn:ietf:rfc:3986 if the Identifier.value itself is a full uri

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.

# snapshot.element[].comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.  The value's primary purpose is computational mapping.  As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.)  A value formatted for human display can be conveyed using the [Rendered Value extension](extension-rendered-value.html).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
II.extension or II.root if system indicates OID or GUID (Or Role.id.extension or root)

# snapshot.element[].short
Time period when id is/was valid for use

# snapshot.element[].definition
Time period during which identifier is/was valid for use.

# snapshot.element[].comment
This is not a duration - that's a measure of time (a separate type), but a duration that occurs at a fixed value of time. A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times"). If duration is required, specify the type as Interval|Duration.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
If present, start SHALL have a lower value than end

# snapshot.element[].constraint[].expression
start.empty() or end.empty() or (start <= end)

# snapshot.element[].mapping[].map
IVL<TS>[lowClosed="true" and highClosed="true"] or URG<TS>[lowClosed="true" and highClosed="true"]

# snapshot.element[].mapping[].map
Role.effectiveTime or implied by context

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The start of the period. The boundary is inclusive.

# snapshot.element[].comment
If the low element is missing, the meaning is that the low boundary is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
End time with inclusive boundary, if not ongoing

# snapshot.element[].definition
The end of the period. If the end of the period is missing, it means that the period is ongoing. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

# snapshot.element[].comment
The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has a end value of 2012-02-03.

# snapshot.element[].meaningWhenMissing
If the end of the period is missing, it means that the period is ongoing

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Organization that issued id (may be just text)

# snapshot.element[].definition
Organization that issued/manages the identifier.

# snapshot.element[].comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
II.assigningAuthorityName but note that this is an improper use by the definition of the field.  Also Role.scoper

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Identifiers assigned to this order instance by the orderer and/or the receiver and/or order fulfiller.

# snapshot.element[].comment
The identifier.type element is used to distinguish between the identifiers assigned by the orderer (known as the 'Placer' in HL7 v2) and the producer of the observations in response to the order (known as the 'Filler' in HL7 v2).  For further discussion and examples see the resource notes section below.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
usual | official | temp | secondary (If known)

# snapshot.element[].comment
This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one. Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

# snapshot.element[].requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Identifies the purpose for this identifier, if known .

# snapshot.element[].definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].comment
This element deals only with general categories of identifiers.  It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage.   Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

# snapshot.element[].requirements
Allows users to make use of identifiers when the identifier system is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].definition
Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

# snapshot.element[].requirements
There are many sets  of identifiers.  To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

# snapshot.element[].example[].valueUri
http://www.acme.com/identifiers/patient or urn:ietf:rfc:3986 if the Identifier.value itself is a full uri

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.

# snapshot.element[].comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.  The value's primary purpose is computational mapping.  As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.)  A value formatted for human display can be conveyed using the [Rendered Value extension](extension-rendered-value.html).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
II.extension or II.root if system indicates OID or GUID (Or Role.id.extension or root)

# snapshot.element[].short
Time period when id is/was valid for use

# snapshot.element[].definition
Time period during which identifier is/was valid for use.

# snapshot.element[].comment
This is not a duration - that's a measure of time (a separate type), but a duration that occurs at a fixed value of time. A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times"). If duration is required, specify the type as Interval|Duration.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
If present, start SHALL have a lower value than end

# snapshot.element[].constraint[].expression
start.empty() or end.empty() or (start <= end)

# snapshot.element[].mapping[].map
IVL<TS>[lowClosed="true" and highClosed="true"] or URG<TS>[lowClosed="true" and highClosed="true"]

# snapshot.element[].mapping[].map
Role.effectiveTime or implied by context

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The start of the period. The boundary is inclusive.

# snapshot.element[].comment
If the low element is missing, the meaning is that the low boundary is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
End time with inclusive boundary, if not ongoing

# snapshot.element[].definition
The end of the period. If the end of the period is missing, it means that the period is ongoing. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

# snapshot.element[].comment
The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has a end value of 2012-02-03.

# snapshot.element[].meaningWhenMissing
If the end of the period is missing, it means that the period is ongoing

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Organization that issued id (may be just text)

# snapshot.element[].definition
Organization that issued/manages the identifier.

# snapshot.element[].comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
II.assigningAuthorityName but note that this is an improper use by the definition of the field.  Also Role.scoper

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Identifiers assigned to this order instance by the orderer and/or the receiver and/or order fulfiller.

# snapshot.element[].comment
The identifier.type element is used to distinguish between the identifiers assigned by the orderer (known as the 'Placer' in HL7 v2) and the producer of the observations in response to the order (known as the 'Filler' in HL7 v2).  For further discussion and examples see the resource notes section below.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
usual | official | temp | secondary (If known)

# snapshot.element[].comment
This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one. Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

# snapshot.element[].requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Identifies the purpose for this identifier, if known .

# snapshot.element[].definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].comment
This element deals only with general categories of identifiers.  It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage.   Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

# snapshot.element[].requirements
Allows users to make use of identifiers when the identifier system is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].definition
Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

# snapshot.element[].requirements
There are many sets  of identifiers.  To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

# snapshot.element[].example[].valueUri
http://www.acme.com/identifiers/patient or urn:ietf:rfc:3986 if the Identifier.value itself is a full uri

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.

# snapshot.element[].comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.  The value's primary purpose is computational mapping.  As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.)  A value formatted for human display can be conveyed using the [Rendered Value extension](extension-rendered-value.html).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
II.extension or II.root if system indicates OID or GUID (Or Role.id.extension or root)

# snapshot.element[].short
Time period when id is/was valid for use

# snapshot.element[].definition
Time period during which identifier is/was valid for use.

# snapshot.element[].comment
This is not a duration - that's a measure of time (a separate type), but a duration that occurs at a fixed value of time. A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times"). If duration is required, specify the type as Interval|Duration.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
If present, start SHALL have a lower value than end

# snapshot.element[].constraint[].expression
start.empty() or end.empty() or (start <= end)

# snapshot.element[].mapping[].map
IVL<TS>[lowClosed="true" and highClosed="true"] or URG<TS>[lowClosed="true" and highClosed="true"]

# snapshot.element[].mapping[].map
Role.effectiveTime or implied by context

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The start of the period. The boundary is inclusive.

# snapshot.element[].comment
If the low element is missing, the meaning is that the low boundary is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
End time with inclusive boundary, if not ongoing

# snapshot.element[].definition
The end of the period. If the end of the period is missing, it means that the period is ongoing. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

# snapshot.element[].comment
The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has a end value of 2012-02-03.

# snapshot.element[].meaningWhenMissing
If the end of the period is missing, it means that the period is ongoing

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Organization that issued id (may be just text)

# snapshot.element[].definition
Organization that issued/manages the identifier.

# snapshot.element[].comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
II.assigningAuthorityName but note that this is an improper use by the definition of the field.  Also Role.scoper

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Protocol or definition followed by this request.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Plan/proposal/order fulfilled by this request.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The request takes the place of the referenced completed or terminated request(s).

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
Handled by message location of ORC (ORC.1=RO or RU)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A shared identifier common to all procedure or diagnostic requests that were authorized more or less simultaneously by a single author, representing the composite or group identifier.

# snapshot.element[].comment
Requests are linked either by a "basedOn" relationship (i.e. one request is fulfilling another) or by having a common requisition. Requests that are part of the same requisition are generally treated independently from the perspective of changing their state or maintaining them after initial creation.

# snapshot.element[].requirements
Some business processes need to know if multiple items were ordered as part of the same "requisition" for billing or other purposes.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
usual | official | temp | secondary (If known)

# snapshot.element[].comment
This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one. Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

# snapshot.element[].requirements
Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Identifies the purpose for this identifier, if known .

# snapshot.element[].definition
A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].comment
This element deals only with general categories of identifiers.  It SHOULD not be used for codes that correspond 1..1 with the Identifier.system. Some identifiers may fall into multiple categories due to common usage.   Where the system is known, a type is unnecessary because the type is always part of the system definition. However systems often need to handle identifiers where the system is not known. There is not a 1:1 relationship between type and system, since many different systems have the same type.

# snapshot.element[].requirements
Allows users to make use of identifiers when the identifier system is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
A coded type for an identifier that can be used to determine which identifier to use for a specific purpose.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].definition
Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

# snapshot.element[].requirements
There are many sets  of identifiers.  To perform matching of two identifiers, we need to know what set we're dealing with. The system identifies a particular set of unique identifiers.

# snapshot.element[].example[].valueUri
http://www.acme.com/identifiers/patient or urn:ietf:rfc:3986 if the Identifier.value itself is a full uri

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The portion of the identifier typically relevant to the user and which is unique within the context of the system.

# snapshot.element[].comment
If the value is a full URI, then the system SHALL be urn:ietf:rfc:3986.  The value's primary purpose is computational mapping.  As a result, it may be normalized for comparison purposes (e.g. removing non-significant whitespace, dashes, etc.)  A value formatted for human display can be conveyed using the [Rendered Value extension](extension-rendered-value.html).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
II.extension or II.root if system indicates OID or GUID (Or Role.id.extension or root)

# snapshot.element[].short
Time period when id is/was valid for use

# snapshot.element[].definition
Time period during which identifier is/was valid for use.

# snapshot.element[].comment
This is not a duration - that's a measure of time (a separate type), but a duration that occurs at a fixed value of time. A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times"). If duration is required, specify the type as Interval|Duration.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
If present, start SHALL have a lower value than end

# snapshot.element[].constraint[].expression
start.empty() or end.empty() or (start <= end)

# snapshot.element[].mapping[].map
IVL<TS>[lowClosed="true" and highClosed="true"] or URG<TS>[lowClosed="true" and highClosed="true"]

# snapshot.element[].mapping[].map
Role.effectiveTime or implied by context

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The start of the period. The boundary is inclusive.

# snapshot.element[].comment
If the low element is missing, the meaning is that the low boundary is not known.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
End time with inclusive boundary, if not ongoing

# snapshot.element[].definition
The end of the period. If the end of the period is missing, it means that the period is ongoing. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

# snapshot.element[].comment
The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has a end value of 2012-02-03.

# snapshot.element[].meaningWhenMissing
If the end of the period is missing, it means that the period is ongoing

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Organization that issued id (may be just text)

# snapshot.element[].definition
Organization that issued/manages the identifier.

# snapshot.element[].comment
The Identifier.assigner may omit the .reference element and only contain a .display element reflecting the name or other textual information about the assigning organization.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].mapping[].map
II.assigningAuthorityName but note that this is an improper use by the definition of the field.  Also Role.scoper

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
draft | active | suspended | completed | entered-in-error | cancelled

# snapshot.element[].comment
The status is generally fully in the control of the requester - they determine whether the order is draft or active and, after it has been activated, competed, cancelled or suspended. States relating to the activities of the performer are reflected on either the corresponding event (see [Event Pattern](event.html) for general discussion) or using the [Task](task.html) resource.  This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
The status of a procedure or diagnostic order.

# snapshot.element[].definition
Whether the request is a proposal, plan, an original order or a reflex order.

# snapshot.element[].comment
This element is labeled as a modifier because the intent alters when and how the resource is actually applicable.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
The kind of procedure or diagnostic request

# snapshot.element[].mapping[].map
.moodCode (nuances beyond PRP/PLAN/RQO would need to be elsewhere)

# snapshot.element[].definition
Indicates how quickly the ProcedureRequest should be addressed with respect to other requests.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].meaningWhenMissing
If missing, this task should be performed with normal priority

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Identifies the level of importance to be assigned to actioning the request

# snapshot.element[].short
True if procedure should not be performed

# snapshot.element[].definition
Set this to true if the record is saying that the procedure should NOT be performed.

# snapshot.element[].comment
This element is labeled as a [modifier](conformance-rules.html#isModifier.html) because it indicates that a procedure shouldn't happen, instead of a request for it to happen.  In general, only the code and timeframe will be present, though occasional additional qualifiers such as body site or even performer could be included to narrow the scope of the prohibition.  If the ProcedureRequest.code and ProcedureRequest.doNotPerform both contain negation, that will reinforce prohibition and should not have a double negative interpretation.

# snapshot.element[].requirements
Used for do not ambulate, do not elevate head of bed, do not flush NG tube, do not take blood pressure on a certain arm, etc.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A code that classifies the procedure for searching, sorting and display purposes (e.g. "Surgical Procedure").

# snapshot.element[].comment
There may be multiple axis of categorization depending on the context or use case for retrieving or displaying the resource.  The level of granularity is defined by the category concepts in the value set.

# snapshot.element[].requirements
Used for filtering what procedure request are retrieved and displayed.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].short
The tests requested by the requesting health care professional.

# snapshot.element[].definition
A code that identifies a particular procedure, diagnostic investigation, or panel of investigations, that have been requested.

# snapshot.element[].comment
Many laboratory and radiology procedure codes embed the specimen/organ system in the test ordeer name, for example,  serum or serum/plasma glucose, or a chest xray. The specimen may not be recorded separately from the test code.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Codes for tests/services that can be performed by procedure or diagnostic services.  For laboratory, LOINC is  (preferred)[http://hl7.org/fhir/STU3/terminologies.html#preferred] and a valueset using LOINC Order codes is available [here](valueset-diagnostic-requests.html).

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].short
A reference to the Patient that the ProcedureRequest is about.

# snapshot.element[].definition
On whom or what the procedure or diagnostic is to be performed. This is usually a human patient, but can also be requested on animals, groups of humans or animals, devices such as dialysis machines, or even locations (typically for environmental scans).

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Encounter or Episode during which request was created

# snapshot.element[].definition
An encounter or episode of care that provides additional information about the healthcare context in which this request is made.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The date/time at which the diagnostic testing should occur.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Preconditions for procedure or diagnostic

# snapshot.element[].definition
If a CodeableConcept is present, it indicates the pre-condition for performing the procedure.  For example "pain", "on flare-up", etc.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
A coded concept identifying the pre-condition that should hold prior to performing a procedure.  For example "pain", "on flare-up", etc.

# snapshot.element[].definition
When the request transitioned to being actionable.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Reference to the resource for the practitioner or organization that created the ProcedureRequest.

# snapshot.element[].definition
The individual who initiated the request and has responsibility for its activation.

# snapshot.element[].comment
This not the dispatcher, but rather who is the authorizer.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The device, practitioner or organization who initiated the request.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The organization the device or practitioner was acting on behalf of.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].requirements
Practitioners and Devices can be associated with multiple organizations.  This element indicates which organization they were acting on behalf of when authoring the request.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Desired type of performer for doing the diagnostic testing.

# snapshot.element[].comment
this is a  role, not  a participation type.  I.e. does not describe the task, but describes the capacity.  For example, “compounding pharmacy” or “psychiatrist” or “internal referral”.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Indicates specific responsibility of an individual within the care team, such as "Primary physician", "Team coordinator", "Caregiver", etc.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].short
Reference to the resource for the practitioner or organization that is requested to perform this request the ProcedureRequest.

# snapshot.element[].definition
The desired perfomer for doing the diagnostic testing.  For example, the surgeon, dermatopathologist, endoscopist, etc.

# snapshot.element[].comment
If needed, use an [extension](extensibility.html) for listing alternative performers and/or roles and/or preference.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
An explanation or justification for why this diagnostic investigation is being requested in coded or textual form.

# snapshot.element[].definition
An explanation or justification for why this diagnostic investigation is being requested in coded or textual form.   This is often for billing purposes.  May relate to the resources referred to in supportingInformation.

# snapshot.element[].comment
This may be used to decide how the diagnostic investigation will be performed, or even if it will be performed at all.   Use CodeableConcept text element if the data is free (uncoded) text as shown in the [CT Scan example](procedurerequest-example-di.html).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Diagnosis or problem codes justifying the reason for requesting the procedure or diagnostic investigation.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].short
A reference to any conditions the patient has that are supplied by the requesting health care professional due to their relevance to the test request.

# snapshot.element[].definition
Indicates another resource that provides a justification for why this diagnostic investigation is being requested.   May relate to the resources referred to in supportingInformation.

# snapshot.element[].comment
This may be used to decide how the diagnostic investigation will be performed, or even if it will be performed at all.   Use CodeableConcept text element if the data is free (uncoded) text as shown in the [CT Scan example](procedurerequest-example-di.html).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Additional clinical information about the patient or specimen that may influence the procedure or diagnostics or their interpretations.     This information includes diagnosis, clinical findings and other observations.  In laboratory ordering these are typically referred to as "ask at order entry questions (AOEs)".  This includes observations explicitly requested by the producer (filler) to provide context or supporting information needed to complete the order. For example,  reporting the amount of inspired oxygen for blood gas measurements.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
One or more specimens that the laboratory procedure will use.

# snapshot.element[].comment
Many diagnostic procedures need a specimen, but the request itself is not actually about the specimen. This element is for when the diagnostic is requested on already existing specimens and the request points to the specimen it applies to.    Conversely, If the request is entered first with an unknown specimen, The [Specimen](specimen.html) resource references to the ProcedureRequest.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Anatomic location where the procedure should be performed. This is the target site.

# snapshot.element[].comment
Only used if not implicit in the code found in ProcedureRequest.type.  If the use case requires BodySite to be handled as a separate resource instead of an inline coded element (e.g. to identify and track separately)  then use the standard extension [procedurerequest-targetBodySite](extension-procedurerequest-targetbodysite.html).

# snapshot.element[].requirements
Knowing where the procedure is performed is important for tracking if multiple sites are possible.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].binding.description
Codes describing anatomical locations. May include laterality.

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
A reference to a code defined by a terminology system.

# snapshot.element[].comment
Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information.  Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

# snapshot.element[].requirements
Allows for translations and alternate encodings within a code system.  Also supports communication of the same instance to systems requiring different encodings.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CE/CNE/CWE subset one of the sets of component 1-3 or 4-6

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].definition
The identification of the code system that defines the meaning of the symbol in the code.

# snapshot.element[].comment
The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...).  OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

# snapshot.element[].requirements
Need to be unambiguous about the source of the definition of the symbol.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
The version of the code system which was used when choosing this code. Note that a well-maintained code system does not need the version reported, because the meaning of codes is consistent across versions. However this cannot consistently be assured. and when the meaning is not guaranteed to be consistent, the version SHOULD be exchanged.

# snapshot.element[].comment
Where the terminology does not clearly define what string should be used to identify code system versions, the recommendation is to use the date (expressed in FHIR date format) on which that version was officially published as the version date.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to refer to a particular code in the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
A representation of the meaning of the code in the system, following the rules of the system.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].requirements
Need to be able to carry a human-readable meaning of the code for readers that do not know  the system.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.2 - but note this is not well followed

# snapshot.element[].short
If this coding was chosen directly by the user

# snapshot.element[].definition
Indicates that this coding was chosen by a user directly - i.e. off a pick list of available items (codes or displays).

# snapshot.element[].comment
Amongst a set of alternatives, a directly chosen code is the most appropriate starting point for new translations. There is some ambiguity about what exactly 'directly chosen' implies, and trading partner agreement may be needed to clarify the use of this element and its consequences more completely.

# snapshot.element[].requirements
This has been identified as a clinical safety criterium - that this exact system/code pair was chosen explicitly, rather than inferred by the system based on some rules or language processing.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
fhir:Coding.userSelected fhir:mapsTo dt:CDCoding.codingRationale. fhir:Coding.userSelected fhir:hasMap fhir:Coding.userSelected.map. fhir:Coding.userSelected.map a fhir:Map;   fhir:target dt:CDCoding.codingRationale. fhir:Coding.userSelected\#true a [     fhir:source "true";     fhir:target dt:CDCoding.codingRationale\#O   ]

# snapshot.element[].short
Plain text representation of the concept

# snapshot.element[].definition
A human language representation of the concept as seen/selected/uttered by the user who entered the data and/or which represents the intended meaning of the user.

# snapshot.element[].comment
Very often the text is the same as a displayName of one of the codings.

# snapshot.element[].requirements
The codes from the terminologies do not always capture the correct meaning with all the nuances of the human using them, or sometimes there is no appropriate code at all. In these cases, the text is used to capture the full meaning of the source.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
C*E.9. But note many systems use C*E.2 for this

# snapshot.element[].short
A human readable explanation from the requesting health care professional containing an explanation on why the test has been requested and any contextual information they considered relevant.

# snapshot.element[].definition
Any other notes and comments made about the service request. For example, letting provider know that "patient hates needles" or other provider instructions.

# snapshot.element[].comment
For systems that do not have structured annotations, they can simply communicate a single annotation with no author or time.  This element may need to be included in narrative because of the potential for modifying information.  *Annotations SHOULD NOT* be used to communicate "modifying" information that could be computable. (This is a SHOULD because enforcing user behavior is nearly impossible).

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Individual responsible for the annotation

# snapshot.element[].definition
The individual responsible for making the annotation.

# snapshot.element[].comment
References SHALL be a reference to an actual FHIR resource, and SHALL be resolveable (allowing for access control, temporary unavailability, etc). Resolution can be either by retrieval from the URL, or, where applicable by resource type, by treating an absolute reference as a canonical URL and looking it up in a local registry/repository.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
Indicates when this particular annotation was made.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].definition
Key events in the history of the request.

# snapshot.element[].comment
This may not include provenances for all versions of the request – only those deemed “relevant” or important. This SHALL NOT include the Provenance associated with this current version of the resource.  (If that provenance is deemed to be a “relevant” change, it will need to be added as part of a later update.  Until then, it can be queried directly as the Provenance that points to this version using _revinclude All Provenances should have some historical version of this Request as their subject.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
SHALL have a contained resource if a local reference is provided

# snapshot.element[].mapping[].map
The target of a resource reference is a RIM entry point (Act, Role, or Entity)

# snapshot.element[].definition
unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

# snapshot.element[].comment
Note that FHIR strings may not exceed 1MB in size

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].slicing.description
Extensions are always sliced by (at least) url

# snapshot.element[].short
Additional Content defined by implementations

# snapshot.element[].definition
May be used to represent additional information that is not part of the basic definition of the element. In order to make the use of extensions safe and manageable, there is a strict set of governance  applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

# snapshot.element[].comment
There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions.  The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].constraint[].human
Must have either extensions or value[x], not both

# snapshot.element[].short
Literal reference, Relative, internal or absolute URL

# snapshot.element[].definition
A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

# snapshot.element[].comment
Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries.   Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].short
Logical reference, when literal reference is not known

# snapshot.element[].definition
An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

# snapshot.element[].comment
When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.   When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# snapshot.element[].mapping[].map
CX / EI (occasionally, more often EI maps to a resource id or a URL)

# snapshot.element[].mapping[].map
II - see see identifier pattern at http://wiki.hl7.org/index.php?title=Common_Design_Patterns#Identifier_Pattern for relevant discussion. The Identifier class is a little looser than the v3 type II because it allows URIs as well as registered OIDs or GUIDs.  Also maps to Role[classCode=IDENT]

# snapshot.element[].definition
Plain text narrative that identifies the resource in addition to the resource reference.

# snapshot.element[].comment
This is generally not the same as the Resource.text of the referenced resource.  The purpose is to identify what's being referenced, not to fully describe it.

# snapshot.element[].constraint[].human
All FHIR elements must have a @value or children

# snapshot.element[].constraint[].expression
hasValue() | (children().count() > id.count())

# differential.element[].short
The tests requested by the requesting health care professional.

# differential.element[].short
A reference to the Patient that the ProcedureRequest is about.

# differential.element[].short
Reference to the resource for the practitioner or organization that created the ProcedureRequest.

# differential.element[].short
Reference to the resource for the practitioner or organization that is requested to perform this request the ProcedureRequest.

# differential.element[].short
An explanation or justification for why this diagnostic investigation is being requested in coded or textual form.

# differential.element[].short
A reference to any conditions the patient has that are supplied by the requesting health care professional due to their relevance to the test request.

# differential.element[].short
A human readable explanation from the requesting health care professional containing an explanation on why the test has been requested and any contextual information they considered relevant.