# description
The Observation resource is used for tracking the current and historical observations that have been made for a patient with further constraints applied to represent duration of the length of time between delivery of the baby and the time spontaneous respiration began, to support the Digital Child Health project.

# snapshot.element[].definition
Measurements and simple assertions made about a patient, device or other subject.

# snapshot.element[].comment
Used for simple observations such as device measurements, laboratory atomic results, vital signs, height, weight, smoking status, comments, etc.  Other resources are used to provide context for observations such as lab reports, etc.

# 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[].constraint[].human
If code is the same as a component code then the value element associated with the code SHALL NOT be present

# snapshot.element[].constraint[].human
dataAbsentReason SHALL only be present if Observation.value[x] is not present

# 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[].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[].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[].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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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[].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
A unique identifier assigned to this observation.

# snapshot.element[].requirements
Allows observations to be distinguished and referenced.

# 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[].mapping[].map
OBX.21  For OBX segments from systems without OBX-21 support a combination of ORC/OBR and OBX must be negotiated between trading partners to uniquely identify the OBX segment. Depending on how V2 has been implemented each of these may be an option: 1) OBR-3 + OBX-3 + OBX-4 or 2) OBR-3 + OBR-4 + OBX-3 + OBX-4 or 2) some other way to uniquely ID the OBR/ORC + OBX-3 + OBX-4.

# 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
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[].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
A plan, proposal or order that is fulfilled in whole or in part by this event.

# 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
Allows tracing of authorization for the event and tracking whether proposals/recommendations were acted upon.

# 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
registered | preliminary | final | amended +

# snapshot.element[].comment
This element is labeled as a modifier because the status contains codes that mark the resource as not currently valid.

# snapshot.element[].requirements
Need to track the status of individual results. Some results are finalized before the whole report is finalized.

# 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 providing the status of an observation.

# snapshot.element[].mapping[].map
status  Amended & Final are differentiated by whether it is the subject of a ControlAct event with a type of "revise"

# snapshot.element[].definition
A code that classifies the general type of observation being made.

# snapshot.element[].comment
In addition to the required category valueset, this element allows various categorization schemes based on the owner’s definition of the category and effectively multiple categories can be used at once.  The level of granularity is defined by the category concepts in the value set.

# snapshot.element[].requirements
Used for filtering what observations 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[].binding.description
Codes for high level observation categories.

# 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
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[].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
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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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 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
Describes what was observed. Sometimes this is called the observation "name".

# snapshot.element[].comment
Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

# snapshot.element[].requirements
Knowing what kind of observation is being made is essential to understanding the observation.

# 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 identifying names of simple observations.

# snapshot.element[].mapping[].map
< 363787002 |Observable entity| OR < 386053000 |Evaluation procedure|

# 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[].short
The SNOMED CT Description ID for the display

# snapshot.element[].definition
The SNOMED CT Description ID for the display.

# 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
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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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 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[].short
Time from delivery to commencement of spontaneous respiration

# 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
The patient, or group of patients, location, or device whose characteristics (direct or indirect) are described by the observation and into whose record the observation is placed.  Comments: Indirect characteristics may be those of a specimen, fetus, donor,  other observer (for example a relative or EMT), or any observation made about the subject.

# snapshot.element[].comment
One would expect this element to be a cardinality  of 1..1.  The only circumstance in which the subject can be missing is when the observation is made by a device that does not know the patient. In this case, the observation SHALL be matched to a patient through some context/channel matching technique, and at this point, the observation should be updated.  If the target of the observation is different than the subject, the general extension [observation-focal-subject](extension-observation-focal-subject.html).  may be used.  However, the distinction between the patient's own value for an observation versus that of the fetus, or the donor or blood product unit, etc., are often specified in the observation code.

# snapshot.element[].requirements
Observations have no value if you don't know who or what they're about.

# 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
Healthcare event during which this observation is made

# snapshot.element[].definition
The healthcare event  (e.g. a patient and healthcare provider interaction) during which this observation is made.

# snapshot.element[].comment
This will typically be the encounter the event occurred within, but some events may be initiated prior to or after the official completion of an encounter or episode but still be tied to the context of the encounter or episode (e.g. pre-admission lab tests).

# snapshot.element[].requirements
For some observations it may be important to know the link between an observation and a particular encounter.

# 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 time or time-period the observed value is asserted as being true. For biological subjects - e.g. human patients - this is usually called the "physiologically relevant time". This is usually either the time of the procedure or of specimen collection, but very often the source of the date/time is not known, only the date/time itself.

# snapshot.element[].comment
At least a date should be present unless this observation is a historical report.

# snapshot.element[].requirements
Knowing when an observation was deemed true is important to its relevance as well as determining trends.

# 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
OBX-14, and/or OBX-19 after v2.4  (depends on who observation made)

# snapshot.element[].definition
The date and time this observation was made available to providers, typically after the results have been reviewed and verified.

# 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
OBR.22 (or MSH.7), or perhaps OBX-19 (depends on who observation made)

# snapshot.element[].definition
Who was responsible for asserting the observed value as "true".

# 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
May give a degree of confidence in the observation and also indicates where follow-up questions should be directed.

# 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 information determined as a result of making the observation, if the information has a simple value.

# snapshot.element[].comment
Normally, an observation will have either a single value or a set of related observations. A few observations (e.g. Apgar score) may have both a value and related observations (for an Apgar score, the observations from which the measure is derived). If a value is present, the datatype for this element should be determined by Observation.code. This element has a variable name depending on the type as follows: valueQuantity, valueCodeableConcept, valueString, valueBoolean, valueRange, valueRatio, valueSampledData, valueAttachment, valueTime, valueDateTime, or valuePeriod. (The name format is "'value' + the type name" with a capital on the first letter of the type).   If the data element is usually coded or if the type associated with the Observation.value defines a coded value, use CodeableConcept instead of string datatype even if the value is uncoded text.  A value set is bound to the ValueCodeableConcept element.    For further discussion and examples see the  [notes section](observation.html#notes) below.

# snapshot.element[].requirements
An observation exists to have a value, though it may not if it is in error, or if it represents a group of observations.

# 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 a code for the unit is present, the system SHALL also be present

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# snapshot.element[].mapping[].map
Event.notDone, Event.notDoneReason  (maps to valeu[x] or dataAbsentReason)

# snapshot.element[].definition
Provides a reason why the expected value in the element Observation.value[x] is missing.

# snapshot.element[].comment
Null or exceptional values can be represented two ways in FHIR Observations.  One way is to simply include them in the value set and represent the exceptions in the value.  For example, measurement values for a serology test could be  "detected", "not detected", "inconclusive", or  "specimen unsatisfactory".   The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values.  For example, the dataAbsentReason code "error" could be used when the measurement was not completed. Note that an observation may only be reported if there are values to report. For example differential cell counts values may be reported only when > 0.  Because of these options, use-case agreements are required to interpret general observations for null or exceptional values.

# snapshot.element[].requirements
For many results it is necessary to handle exceptional values in measurements.

# 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 specifying why the result (Observation.value[x]) is missing.

# snapshot.element[].mapping[].map
Event.notDone, Event.notDoneReason  (maps to valeu[x] or dataAbsentReason)

# 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[].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
The assessment made based on the result of the observation.  Intended as a simple compact code often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result. Otherwise known as abnormal flag.

# snapshot.element[].comment
Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

# snapshot.element[].requirements
For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

# 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[].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
May include statements about significant, unexpected or unreliable values, or information about the source of the value where this may be relevant to the interpretation of the result.

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

# snapshot.element[].requirements
Need to be able to provide free text additional information.

# 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
NTE.3 (partner NTE to OBX, or sometimes another (child?) OBX)

# snapshot.element[].definition
Indicates the site on the subject's body where the observation was made (i.e. the target site).

# snapshot.element[].comment
Only used if not implicit in code found in Observation.code.  In many systems, this may be represented as a related observation instead of an inline component.   If the use case requires BodySite to be handled as a separate resource (e.g. to identify and track separately) then use the standard extension[ body-site-instance](extension-body-site-instance.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
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
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[].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
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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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 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
Indicates the mechanism used to perform the observation.

# snapshot.element[].comment
Only used if not implicit in code for Observation.code.

# snapshot.element[].requirements
In some cases, method can impact results and is thus used for determining whether results can be compared or determining significance of results.

# 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
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[].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
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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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 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
The specimen that was used when this observation was made.

# snapshot.element[].comment
Should only be used if not implicit in code found in `Observation.code`.  Observations are not made on specimens themselves; they are made on a subject, but in many cases by the means of a specimen. Note that although specimens are often involved, they are not always tracked and reported explicitly. Also note that observation resources may be used in contexts that track the specimen explicitly (e.g. Diagnostic Report).

# 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 device used to generate the observation data.

# snapshot.element[].comment
An extension should be used if further typing of the device is needed.  Devices used to support obtaining an observation can be represented using either an extension or through the Observation.related element.

# 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
Guidance on how to interpret the value by comparison to a normal or recommended range.

# snapshot.element[].comment
Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this may not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

# snapshot.element[].requirements
Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

# 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 at least a low or a high or text

# snapshot.element[].constraint[].expression
low.exists() or high.exists() or text.exists()

# 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 value of the low bound of the reference range.  The low bound of the reference range endpoint is inclusive of the value (e.g.  reference range is >=5 - <=9).   If the low bound is omitted,  it is assumed to be meaningless (e.g. reference range is <=2.3).

# snapshot.element[].comment
The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use may also restrict the values for the comparator.

# 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 a code for the unit is present, the system SHALL also be present

# snapshot.element[].constraint[].human
The comparator is not used on a SimpleQuantity

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# 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
Numerical value (with implicit precision)

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# 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
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].comment
This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# 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
How the Quantity should be understood and represented.

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

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# 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 identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# 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 computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.  The context of use may additionally require a code from a particular system.

# snapshot.element[].requirements
Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

# 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 value of the high bound of the reference range.  The high bound of the reference range endpoint is inclusive of the value (e.g.  reference range is >=5 - <=9).   If the high bound is omitted,  it is assumed to be meaningless (e.g. reference range is >= 2.3).

# snapshot.element[].comment
The context of use may frequently define what kind of quantity this is and therefore what kind of units can be used. The context of use may also restrict the values for the comparator.

# 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 a code for the unit is present, the system SHALL also be present

# snapshot.element[].constraint[].human
The comparator is not used on a SimpleQuantity

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# 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
Numerical value (with implicit precision)

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# 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
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].comment
This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# 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
How the Quantity should be understood and represented.

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

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# 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 identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# 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 computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.  The context of use may additionally require a code from a particular system.

# snapshot.element[].requirements
Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

# 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
Codes to indicate the what part of the targeted reference population it applies to. For example, the normal or therapeutic range.

# snapshot.element[].comment
This SHOULD be populated if there is more than one range.  If this element is not present then the normal range is assumed.

# snapshot.element[].requirements
Need to be able to say what kind of reference range this is - normal, recommended, therapeutic, etc,  - for proper 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[].binding.description
Code for the meaning of a reference range.

# snapshot.element[].mapping[].map
< 260245000 |Findings values| OR   < 365860008 |General clinical state finding|  OR  < 250171008 |Clinical history or observation findings| OR   < 415229000 |Racial group| OR  < 365400002 |Finding of puberty stage| OR < 443938003 |Procedure carried out on subject|

# 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[].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
Codes to indicate the target population this reference range applies to.  For example, a reference range may be based on the normal population or a particular sex or race.

# snapshot.element[].comment
This SHOULD be populated if there is more than one range.  If this element is not present then the normal population is assumed.

# snapshot.element[].requirements
Need to be able to identify the target population for proper 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[].binding.description
Codes identifying the population the reference range applies to.

# snapshot.element[].mapping[].map
< 260245000 |Findings values| OR   < 365860008 |General clinical state finding|  OR  < 250171008 |Clinical history or observation findings| OR   < 415229000 |Racial group| OR  < 365400002 |Finding of puberty stage| OR < 443938003 |Procedure carried out on subject|

# 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[].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
The age at which this reference range is applicable. This is a neonatal age (e.g. number of weeks at term) if the meaning says so.

# snapshot.element[].comment
The stated low and high value are assumed to have arbitrarily high precision when it comes to determining which values are in the range. I.e. 1.99 is not in the range 2 -> 3.

# 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, low SHALL have a lower value than high

# snapshot.element[].constraint[].expression
low.empty() or high.empty() or (low <= high)

# snapshot.element[].mapping[].map
NR and also possibly SN (but see also quantity)

# 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 low limit. The boundary is inclusive.

# snapshot.element[].comment
If the low element is missing, 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[].constraint[].human
If a code for the unit is present, the system SHALL also be present

# snapshot.element[].constraint[].human
The comparator is not used on a SimpleQuantity

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# 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
Numerical value (with implicit precision)

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# 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
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].comment
This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# 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
How the Quantity should be understood and represented.

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

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# 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 identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# 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 computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.  The context of use may additionally require a code from a particular system.

# snapshot.element[].requirements
Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

# 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 high limit. The boundary is inclusive.

# snapshot.element[].comment
If the high element is missing, the high 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[].constraint[].human
If a code for the unit is present, the system SHALL also be present

# snapshot.element[].constraint[].human
The comparator is not used on a SimpleQuantity

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# 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
Numerical value (with implicit precision)

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# 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
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].comment
This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# 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
How the Quantity should be understood and represented.

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

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# 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 identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# 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 computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.  The context of use may additionally require a code from a particular system.

# snapshot.element[].requirements
Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

# 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 based reference range in an observation

# snapshot.element[].definition
Text based reference range in an observation which may be used when a quantitative range is not appropriate for an observation.  An example would be a reference value of "Negative" or a list or table of 'normals'.

# 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
A  reference to another resource (usually another Observation) whose relationship is defined by the relationship type code.

# snapshot.element[].comment
For a discussion on the ways Observations can assembled in groups together see [Notes below](observation.html#4.20.4).

# snapshot.element[].requirements
Normally, an observation will have either a value or a set of related observations. A few observations (e.g. Apgar score) may have both a value and a set of related observations or sometimes a QuestionnaireResponse from which the measure is derived.

# 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
Relationships established by OBX-4 usage

# 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[].short
has-member | derived-from | sequel-to | replaces | qualified-by | interfered-by

# snapshot.element[].definition
A code specifying the kind of relationship that exists with the target resource.

# snapshot.element[].comment
The "derived-from" type is the only logical choice when referencing the QuestionnaireAnswer 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[].binding.description
Codes specifying how two observations are related.

# snapshot.element[].definition
A reference to the observation or [QuestionnaireResponse](questionnaireresponse.html#) resource that is related to this observation.

# 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[].slicing.description
Component observations which form the observation of the duration of the length of time between delivery of the baby and the time spontaneous respiration began.

# snapshot.element[].definition
Some observations have multiple component observations.  These component observations are expressed as separate code value pairs that share the same attributes.  Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

# snapshot.element[].comment
For a discussion on the ways Observations can be assembled in groups together see [Notes](observation.html#notes) below.

# snapshot.element[].requirements
Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable).   However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

# 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[].short
Type of component observation (code / type)

# snapshot.element[].definition
Describes what was observed. Sometimes this is called the observation "code".

# snapshot.element[].comment
Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

# snapshot.element[].requirements
Knowing what kind of observation is being made is essential to understanding the observation.

# 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 identifying names of simple observations.

# snapshot.element[].mapping[].map
< 363787002 |Observable entity| OR  < 386053000 |Evaluation procedure|

# 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[].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
The information determined as a result of making the observation, if the information has a simple value.

# snapshot.element[].comment
Normally, an observation will have either a single value or a set of related observations. A few observations (e.g. Apgar score) may have both a value and related observations (for an Apgar score, the observations from which the measure is derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value.   For boolean values use valueCodeableConcept and select codes from <http://hl7.org/fhir/ValueSet/v2-0136> (these "yes/no" concepts can be mapped to the display name "true/false" or other mutually exclusive terms that may be needed").  The element, Observation.value[x], has a variable name depending on the type as follows: valueQuantity, valueCodeableConcept, valueRatio, valueChoice, valuePeriod, valueSampleData, or valueString (the name format is "'value' + the type name" with a capital on the first letter of the type).

# snapshot.element[].requirements
An observation exists to have a value, though it may not if it is in error, or if it represents a group of observations.

# 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 a code for the unit is present, the system SHALL also be present

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# snapshot.element[].definition
Provides a reason why the expected value in the element Observation.value[x] is missing.

# snapshot.element[].comment
"Null" or exceptional values can be represented two ways in FHIR Observations.  One way is to simply include them in the value set and represent the exceptions in the value.  For example, measurement values for a serology test could be  "detected", "not detected", "inconclusive", or  "test not done".   The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values.  For example, the dataAbsentReason code "error" could be used when the measurement was not completed.  Because of these options, use-case agreements are required to interpret general observations for exceptional values.

# snapshot.element[].requirements
For many results it is necessary to handle exceptional values in measurements.

# 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 specifying why the result (Observation.value[x]) is missing.

# 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[].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
The assessment made based on the result of the observation.  Intended as a simple compact code often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result. Otherwise known as abnormal flag.

# snapshot.element[].comment
The component interpretation applies only to the individual component value.  For an overall interpretation all components together use thes Observation.interpretation element.

# snapshot.element[].requirements
For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

# 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[].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
Provides guide for interpretation of component result

# snapshot.element[].definition
Guidance on how to interpret the value by comparison to a normal or recommended range.

# snapshot.element[].comment
Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this may not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

# snapshot.element[].requirements
Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

# snapshot.element[].short
Number of minutes applicable to the spontaneous respiration onset observation, expressed in n2 format

# snapshot.element[].definition
Some observations have multiple component observations.  These component observations are expressed as separate code value pairs that share the same attributes.  Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

# snapshot.element[].comment
For a discussion on the ways Observations can be assembled in groups together see [Notes](observation.html#notes) below.

# snapshot.element[].requirements
Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable).   However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

# 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[].short
Code representing the component observation of 'minutes'

# snapshot.element[].definition
Describes what was observed. Sometimes this is called the observation "code".

# snapshot.element[].comment
Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

# snapshot.element[].requirements
Knowing what kind of observation is being made is essential to understanding the observation.

# 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 identifying names of simple observations.

# snapshot.element[].mapping[].map
< 363787002 |Observable entity| OR  < 386053000 |Evaluation procedure|

# 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[].short
The SNOMED CT Description ID for the display

# snapshot.element[].definition
The SNOMED CT Description ID for the display.

# 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
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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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 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
Number of minutes applicable to the spontaneous respiration onset observation

# snapshot.element[].definition
The information determined as a result of making the observation, if the information has a simple value.

# snapshot.element[].comment
Normally, an observation will have either a single value or a set of related observations. A few observations (e.g. Apgar score) may have both a value and related observations (for an Apgar score, the observations from which the measure is derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value.   For boolean values use valueCodeableConcept and select codes from <http://hl7.org/fhir/ValueSet/v2-0136> (these "yes/no" concepts can be mapped to the display name "true/false" or other mutually exclusive terms that may be needed").  The element, Observation.value[x], has a variable name depending on the type as follows: valueQuantity, valueCodeableConcept, valueRatio, valueChoice, valuePeriod, valueSampleData, or valueString (the name format is "'value' + the type name" with a capital on the first letter of the type).

# snapshot.element[].requirements
An observation exists to have a value, though it may not if it is in error, or if it represents a group of observations.

# 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 a code for the unit is present, the system SHALL also be present

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# 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
Number of minutes applicable to the spontaneous respiration onset observation, expressed in n2 format

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# 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
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].definition
How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

# snapshot.element[].comment
This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# 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
How the Quantity should be understood and represented.

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

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# 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 identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# 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 computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.  The context of use may additionally require a code from a particular system.

# snapshot.element[].requirements
Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

# 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
Provides a reason why the expected value in the element Observation.value[x] is missing.

# snapshot.element[].comment
"Null" or exceptional values can be represented two ways in FHIR Observations.  One way is to simply include them in the value set and represent the exceptions in the value.  For example, measurement values for a serology test could be  "detected", "not detected", "inconclusive", or  "test not done".   The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values.  For example, the dataAbsentReason code "error" could be used when the measurement was not completed.  Because of these options, use-case agreements are required to interpret general observations for exceptional values.

# snapshot.element[].requirements
For many results it is necessary to handle exceptional values in measurements.

# 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 specifying why the result (Observation.value[x]) is missing.

# 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[].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
The assessment made based on the result of the observation.  Intended as a simple compact code often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result. Otherwise known as abnormal flag.

# snapshot.element[].comment
The component interpretation applies only to the individual component value.  For an overall interpretation all components together use thes Observation.interpretation element.

# snapshot.element[].requirements
For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

# 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[].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
Provides guide for interpretation of component result

# snapshot.element[].definition
Guidance on how to interpret the value by comparison to a normal or recommended range.

# snapshot.element[].comment
Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this may not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

# snapshot.element[].requirements
Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

# snapshot.element[].short
Number of seconds applicable to the spontaneous respiration onset observation, expressed in n2 format

# snapshot.element[].definition
Some observations have multiple component observations.  These component observations are expressed as separate code value pairs that share the same attributes.  Examples include systolic and diastolic component observations for blood pressure measurement and multiple component observations for genetics observations.

# snapshot.element[].comment
For a discussion on the ways Observations can be assembled in groups together see [Notes](observation.html#notes) below.

# snapshot.element[].requirements
Component observations share the same attributes in the Observation resource as the primary observation and are always treated a part of a single observation (they are not separable).   However, the reference range for the primary observation value is not inherited by the component values and is required when appropriate for each component observation.

# 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[].short
Code representing the component observation of 'seconds'

# snapshot.element[].definition
Describes what was observed. Sometimes this is called the observation "code".

# snapshot.element[].comment
Not all terminology uses fit this general pattern. In some cases, models should not use CodeableConcept and use Coding directly and provide their own structure for managing text, codings, translations and the relationship between elements and pre- and post-coordination.

# snapshot.element[].requirements
Knowing what kind of observation is being made is essential to understanding the observation.

# 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 identifying names of simple observations.

# snapshot.element[].mapping[].map
< 363787002 |Observable entity| OR  < 386053000 |Evaluation procedure|

# 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[].short
The SNOMED CT Description ID for the display

# snapshot.element[].definition
The SNOMED CT Description ID for the display.

# 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
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
Source of the definition for the extension code - a logical name or a URL.

# snapshot.element[].comment
The definition may point directly to a computable or human-readable definition of the extensibility codes, or it may be a logical URI as declared in some other specification. The definition SHALL be a URI for the Structure Definition defining the extension.

# 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
Value of extension - may be a resource or one of a constrained set of the data types (see Extensibility in the spec for list).

# 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 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
Number of seconds applicable to the spontaneous respiration onset observation

# snapshot.element[].definition
The information determined as a result of making the observation, if the information has a simple value.

# snapshot.element[].comment
Normally, an observation will have either a single value or a set of related observations. A few observations (e.g. Apgar score) may have both a value and related observations (for an Apgar score, the observations from which the measure is derived). If a value is present, the datatype for this element should be determined by Observation.code. A CodeableConcept with just a text would be used instead of a string if the field was usually coded, or if the type associated with the Observation.code defines a coded value.   For boolean values use valueCodeableConcept and select codes from <http://hl7.org/fhir/ValueSet/v2-0136> (these "yes/no" concepts can be mapped to the display name "true/false" or other mutually exclusive terms that may be needed").  The element, Observation.value[x], has a variable name depending on the type as follows: valueQuantity, valueCodeableConcept, valueRatio, valueChoice, valuePeriod, valueSampleData, or valueString (the name format is "'value' + the type name" with a capital on the first letter of the type).

# snapshot.element[].requirements
An observation exists to have a value, though it may not if it is in error, or if it represents a group of observations.

# 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 a code for the unit is present, the system SHALL also be present

# snapshot.element[].mapping[].map
PQ, IVL<PQ>, MO, CO, depending on the values

# 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
Number of seconds applicable to the spontaneous respiration onset observation, expressed in n2 format

# snapshot.element[].definition
The value of the measured amount. The value includes an implicit precision in the presentation of the value.

# snapshot.element[].comment
The implicit precision in the value should always be honored. Monetary values have their own rules for handling precision (refer to standard accounting text books).

# snapshot.element[].requirements
Precision is handled implicitly in almost all cases of measurement.

# 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
PQ.value, CO.value, MO.value, IVL.high or IVL.low depending on the value

# snapshot.element[].short
< | <= | >= | > - how to understand the value

# snapshot.element[].definition
How the value should be understood and represented - whether the actual value is greater or less than the stated value due to measurement issues; e.g. if the comparator is "<" , then the real value is < stated value.

# snapshot.element[].comment
This is labeled as "Is Modifier" because the comparator modifies the interpretation of the value significantly. If there is no comparator, then there is no modification of the value.

# snapshot.element[].requirements
Need a framework for handling measures where the value is <5ug/L or >400mg/L due to the limitations of measuring methodology.

# snapshot.element[].meaningWhenMissing
If there is no comparator, then there is no modification of the value

# 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
How the Quantity should be understood and represented.

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

# snapshot.element[].requirements
There are many representations for units of measure and in many contexts, particular representations are fixed and required. I.e. mcg for micrograms.

# 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 identification of the system that provides the coded form of the unit.

# snapshot.element[].requirements
Need to know the system that defines the coded form of the unit.

# 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 computer processable form of the unit in some unit representation system.

# snapshot.element[].comment
The preferred system is UCUM, but SNOMED CT can also be used (for customary units) or ISO 4217 for currency.  The context of use may additionally require a code from a particular system.

# snapshot.element[].requirements
Need a computable form of the unit that is fixed across all forms. UCUM provides this for quantities, but SNOMED CT provides many units of interest.

# 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
Provides a reason why the expected value in the element Observation.value[x] is missing.

# snapshot.element[].comment
"Null" or exceptional values can be represented two ways in FHIR Observations.  One way is to simply include them in the value set and represent the exceptions in the value.  For example, measurement values for a serology test could be  "detected", "not detected", "inconclusive", or  "test not done".   The alternate way is to use the value element for actual observations and use the explicit dataAbsentReason element to record exceptional values.  For example, the dataAbsentReason code "error" could be used when the measurement was not completed.  Because of these options, use-case agreements are required to interpret general observations for exceptional values.

# snapshot.element[].requirements
For many results it is necessary to handle exceptional values in measurements.

# 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 specifying why the result (Observation.value[x]) is missing.

# 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[].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
The assessment made based on the result of the observation.  Intended as a simple compact code often placed adjacent to the result value in reports and flow sheets to signal the meaning/normalcy status of the result. Otherwise known as abnormal flag.

# snapshot.element[].comment
The component interpretation applies only to the individual component value.  For an overall interpretation all components together use thes Observation.interpretation element.

# snapshot.element[].requirements
For some results, particularly numeric results, an interpretation is necessary to fully understand the significance of a result.

# 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[].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
Provides guide for interpretation of component result

# snapshot.element[].definition
Guidance on how to interpret the value by comparison to a normal or recommended range.

# snapshot.element[].comment
Most observations only have one generic reference range. Systems MAY choose to restrict to only supplying the relevant reference range based on knowledge about the patient (e.g., specific to the patient's age, gender, weight and other factors), but this may not be possible or appropriate. Whenever more than one reference range is supplied, the differences between them SHOULD be provided in the reference range and/or age properties.

# snapshot.element[].requirements
Knowing what values are considered "normal" can help evaluate the significance of a particular result. Need to be able to provide multiple reference ranges for different contexts.

# differential.element[].short
The SNOMED CT Description ID for the display

# differential.element[].definition
The SNOMED CT Description ID for the display.

# differential.element[].short
Time from delivery to commencement of spontaneous respiration

# differential.element[].slicing.description
Component observations which form the observation of the duration of the length of time between delivery of the baby and the time spontaneous respiration began.

# differential.element[].short
Number of minutes applicable to the spontaneous respiration onset observation, expressed in n2 format

# differential.element[].short
Code representing the component observation of 'minutes'

# differential.element[].short
The SNOMED CT Description ID for the display

# differential.element[].definition
The SNOMED CT Description ID for the display.

# differential.element[].short
Number of minutes applicable to the spontaneous respiration onset observation

# differential.element[].short
Number of minutes applicable to the spontaneous respiration onset observation, expressed in n2 format

# differential.element[].short
Number of seconds applicable to the spontaneous respiration onset observation, expressed in n2 format

# differential.element[].short
Code representing the component observation of 'seconds'

# differential.element[].short
The SNOMED CT Description ID for the display

# differential.element[].definition
The SNOMED CT Description ID for the display.

# differential.element[].short
Number of seconds applicable to the spontaneous respiration onset observation

# differential.element[].short
Number of seconds applicable to the spontaneous respiration onset observation, expressed in n2 format