Polaris FHIR Implementation Guide
1.9.2 - ci-build

Polaris FHIR Implementation Guide - Local Development build (v1.9.2) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Resource Profile: PolarisCoreAppState - Detailed Descriptions

Active as of 2025-10-08

Definitions for the polaris-core-appstate resource profile.

Guidance on how to interpret the contents of this table can be foundhere

0. Basic
Definition

Represents application state information for Polaris applications, capturing key details like state type, content, and associated resources using standard Polaris references. Uses instance-specific identifiers for tracking application state across systems.


Basic is used for handling concepts not yet defined in FHIR, narrative-only resources that don't map to an existing resource, and custom resources not appropriate for inclusion in the FHIR specification.

ShortPolaris App State CoreResource for non-supported content
Control0..*
Is Modifierfalse
Summaryfalse
Alternate NamesZ-resource, Extension-resource, Custom-resource
Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
dom-6: A resource should have narrative for robust management (text.`div`.exists())
2. Basic.meta
Definition

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

ShortMetadata about the resource
Control0..1
TypeMeta
Is Modifierfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
4. Basic.meta.source
Definition

A URI that identifies the EMR pipeline and version from which this resource originated. This tells you which EMR instance (recommend using the instance identifier), and the version of the pipeline code/transformations.


A uri that identifies the source system of the resource. This provides a minimal amount of Provenance information that can be used to track or differentiate the source of information in the resource. The source may identify another FHIR server, document, message, database, etc.

ShortIdentifies EMR instance & pipeline version the resource came fromIdentifies where the resource comes from
Comments

In the provenance resource, this corresponds to Provenance.entity.what[x]. The exact use of the source (and the implied Provenance.entity.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used.

This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL.

Control0..1
Typeuri
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. Basic.implicitRules
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. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

ShortA set of rules under which this content was created
Comments

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. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

Control0..1
Typeuri
Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
8. Basic.text
Definition

A human-readable narrative summary of the PolarisCoreAppState resource for human interpretation.


A human-readable narrative that contains a summary of the resource and can 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.

ShortNarrativeText summary of the resource, for human interpretation
Comments

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 information is added later.

Control0..1
TypeNarrative
Is Modifierfalse
Must Supporttrue
Summaryfalse
Alternate Namesnarrative, html, xhtml, display
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
10. Basic.extension
Definition

Contains the application state values using type-specific extensions (string, boolean, etc.).


May be used to represent additional information that is not part of the basic definition of the resource. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

ShortThe actual state value(s) - can have an arbitrary number of state valuesAdditional content defined by implementations
Comments

Different extension types support different value data types.


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.

Control10..*
TypeExtension
Is Modifierfalse
Must Supporttrue
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
12. Basic.extension.url
Definition

Identifies which type of value extension is being used (string, boolean, etc.).


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

ShortExtension type URLidentifies the meaning of the extension
Comments

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.

Control1..1
Typeuri
Is Modifierfalse
Must Supporttrue
XML FormatIn the XML format, this property is represented as an attribute.
Summaryfalse
14. Basic.modifierExtension
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 and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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.

Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

ShortExtensions that cannot be ignored
Comments

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.

Control0..*
TypeExtension
Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
Summaryfalse
Requirements

Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
16. Basic.identifier
Definition

Optional identifier for this application state entry.


Identifier assigned to the resource for business purposes, outside the context of FHIR.

ShortBusiness identifier for app state
Comments

Most app state entries are identified by their code and subject rather than explicit identifiers.

NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1*
TypeIdentifier
Is Modifierfalse
Must Supporttrue
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
18. Basic.code
Definition

Identifies what kind of application state this represents and which application namespace it belongs to.


Identifies the 'type' of resource - equivalent to the resource name for other resources.

ShortType and namespace of application stateKind of Resource
Comments

The code acts as both a type discriminator and namespace identifier for the state data.


Because resource references will only be able to indicate 'Basic', the type of reference will need to be specified in a Profile identified as part of the resource. Refer to the resource notes section for information on appropriate terminologies for this code.

This element is labeled as a modifier because it defines the meaning of the resource and cannot be ignored.

Control1..1
BindingFor example codes, see BasicResourceTypeshttp://hl7.org/fhir/ValueSet/basic-resource-type|4.0.1
(example to http://hl7.org/fhir/ValueSet/basic-resource-type|4.0.1)

Codes for identifying types of resources not yet defined by FHIR.

TypeCodeableConcept
Is Modifiertrue because This element determines what kind of resource is being represented which drives the meaning of all of the other elements.
Must Supporttrue
Summarytrue
Requirements

Must be able to distinguish different types of Basic resources.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
20. Basic.code.coding
Definition

The coded representation of the application state type.


A reference to a code defined by a terminology system.

ShortCoded type of stateCode defined by a terminology system
Comments

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.

Control10..1*
TypeCoding
Is Modifierfalse
Must Supporttrue
Summarytrue
Requirements

Allows for alternative encodings within a code system, and translations to other code systems.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
app-state-system-inv: AppState coding.system must match Polaris CodeSystem URL rules. (system.matches('https://fhir.apps.health/CodeSystem/[a-zA-Z0-9.-]+-app-state'))
22. Basic.code.coding.system
Definition

Must follow pattern: https://fhir.apps.health/CodeSystem/[app-name]-app-state


The identification of the code system that defines the meaning of the symbol in the code.

ShortApplication-specific CodeSystem URLIdentity of the terminology system
Comments

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 reference to some definition that establishes the system clearly and unambiguously.

Control10..1
Typeuri
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Requirements

Need to be unambiguous about the source of the definition of the symbol.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
24. Basic.code.coding.code
Definition

The specific type of state within the application's namespace.


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).

ShortSpecific state type codeSymbol in syntax defined by the system
Control10..1
Typecode
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Requirements

Need to refer to a particular code in the system.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
26. Basic.code.coding.display
Definition

A representation of the meaning of the code in the system, following the rules of the system.

ShortHuman-readable state type nameRepresentation defined by the system
Control0..1
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Requirements

Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
28. Basic.code.text
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.

ShortPlain text description of state typePlain text representation of the concept
Comments

Very often the text is the same as a displayName of one of the codings.

Control0..1
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
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.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
30. Basic.subject
Definition

The FHIR resource (Patient, PractitionerRole, Organization, etc.) that this application state is associated with.


Identifies the patient, practitioner, device or any other resource that is the "focus" of this resource.

ShortResource this state is associated withIdentifies the focus of this resource
Comments

Application state is always linked to a specific resource for context.


Optional as not all potential resources will have subjects. Resources associated with multiple subjects can handle this via extension.

Control10..1
TypeReference(Polaris Patient Core, Polaris PractitionerRole Core, Polaris Organization Core, Resource)
Is Modifierfalse
Summarytrue
Requirements

Needed for partitioning the resource by Patient.

Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
32. Basic.subject.reference
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.

ShortReference to the associated resourceLiteral reference, Relative, internal or absolute URL
Comments

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.

Control0..1
This element is affected by the following invariants: ref-1
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
34. Basic.subject.type
Definition

The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

ShortType of resource referencedType the reference refers to (e.g. "Patient")
Comments

This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

Control0..1
BindingUnless not suitable, these codes SHALL be taken from ResourceTypehttp://hl7.org/fhir/ValueSet/resource-types|4.0.1
(extensible to http://hl7.org/fhir/ValueSet/resource-types|4.0.1)

Aa resource (or, for logical models, the URI of the logical model).

Typeuri
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
36. Basic.subject.display
Definition

Plain text narrative that identifies the resource in addition to the resource reference.

ShortDisplay name of referenced resourceText alternative for the resource
Comments

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.

Control0..1
Typestring
Is Modifierfalse
Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
Must Supporttrue
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))

Guidance on how to interpret the contents of this table can be foundhere

0. Basic
Definition

Represents application state information for Polaris applications, capturing key details like state type, content, and associated resources using standard Polaris references. Uses instance-specific identifiers for tracking application state across systems.

ShortPolaris App State Core
2. Basic.meta
4. Basic.meta.source
Definition

A URI that identifies the EMR pipeline and version from which this resource originated. This tells you which EMR instance (recommend using the instance identifier), and the version of the pipeline code/transformations.

ShortIdentifies EMR instance & pipeline version the resource came from
Must Supporttrue
6. Basic.text
Definition

A human-readable narrative summary of the PolarisCoreAppState resource for human interpretation.

ShortNarrative
Must Supporttrue
8. Basic.extension
Definition

Contains the application state values using type-specific extensions (string, boolean, etc.).

ShortThe actual state value(s) - can have an arbitrary number of state values
Comments

Different extension types support different value data types.

Control1..?
Must Supporttrue
10. Basic.extension.url
Definition

Identifies which type of value extension is being used (string, boolean, etc.).

ShortExtension type URL
Must Supporttrue
12. Basic.identifier
Definition

Optional identifier for this application state entry.

ShortBusiness identifier for app state
Comments

Most app state entries are identified by their code and subject rather than explicit identifiers.

NoteThis is a business identifier, not a resource identifier (see discussion)
Control0..1
Must Supporttrue
14. Basic.code
Definition

Identifies what kind of application state this represents and which application namespace it belongs to.

ShortType and namespace of application state
Comments

The code acts as both a type discriminator and namespace identifier for the state data.

Must Supporttrue
16. Basic.code.coding
Definition

The coded representation of the application state type.

ShortCoded type of state
Control1..1
Must Supporttrue
Invariantsapp-state-system-inv: AppState coding.system must match Polaris CodeSystem URL rules. (system.matches('https://fhir.apps.health/CodeSystem/[a-zA-Z0-9.-]+-app-state'))
18. Basic.code.coding.system
Definition

Must follow pattern: https://fhir.apps.health/CodeSystem/[app-name]-app-state

ShortApplication-specific CodeSystem URL
Control1..?
Must Supporttrue
20. Basic.code.coding.code
Definition

The specific type of state within the application's namespace.

ShortSpecific state type code
Control1..?
Must Supporttrue
22. Basic.code.coding.display
ShortHuman-readable state type name
Must Supporttrue
24. Basic.code.text
ShortPlain text description of state type
Must Supporttrue
26. Basic.subject
Definition

The FHIR resource (Patient, PractitionerRole, Organization, etc.) that this application state is associated with.

ShortResource this state is associated with
Comments

Application state is always linked to a specific resource for context.

Control1..?
TypeReference(Polaris Patient Core, Polaris PractitionerRole Core, Polaris Organization Core)
28. Basic.subject.reference
ShortReference to the associated resource
Must Supporttrue
30. Basic.subject.type
ShortType of resource referenced
Must Supporttrue
32. Basic.subject.display
ShortDisplay name of referenced resource
Must Supporttrue

Guidance on how to interpret the contents of this table can be foundhere

0. Basic
Definition

Represents application state information for Polaris applications, capturing key details like state type, content, and associated resources using standard Polaris references. Uses instance-specific identifiers for tracking application state across systems.

ShortPolaris App State Core
Control0..*
Is Modifierfalse
Summaryfalse
Alternate NamesZ-resource, Extension-resource, Custom-resource
Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
dom-6: A resource should have narrative for robust management (text.`div`.exists())
2. Basic.id
Definition

The logical id of the resource, as used in the URL for the resource. Once assigned, this value never changes.

ShortLogical id of this artifact
Comments

The only time that a resource does not have an id is when it is being submitted to the server using a create operation.

Control0..1
Typeid
Is Modifierfalse
Summarytrue
4. Basic.meta
Definition

The metadata about the resource. This is content that is maintained by the infrastructure. Changes to the content might not always be associated with version changes to the resource.

ShortMetadata about the resource
Control0..1
TypeMeta
Is Modifierfalse
Summarytrue
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
6. Basic.meta.id
Definition

Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

ShortUnique id for inter-element referencing
Control0..1
Typestring
Is Modifierfalse
XML FormatIn the XML format, this property is represented as an attribute.
Summaryfalse
8. Basic.meta.extension
Definition

May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

ShortAdditional content defined by implementations
Comments

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.

Control0..*
TypeExtension
Is Modifierfalse
Summaryfalse
Alternate Namesextensions, user content
Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
SlicingThis element introduces a set of slices on Basic.meta.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 10. Basic.meta.versionId
    Definition

    The version specific identifier, as it appears in the version portion of the URL. This value changes when the resource is created, updated, or deleted.

    ShortVersion specific identifier
    Comments

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

    Control0..1
    Typeid
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    12. Basic.meta.lastUpdated
    Definition

    When the resource last changed - e.g. when the version changed.

    ShortWhen the resource version last changed
    Comments

    This value is always populated except when the resource is first being created. The server / resource manager sets this value; what a client provides is irrelevant. This is equivalent to the HTTP Last-Modified and SHOULD have the same value on a read interaction.

    Control0..1
    Typeinstant
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    14. Basic.meta.source
    Definition

    A URI that identifies the EMR pipeline and version from which this resource originated. This tells you which EMR instance (recommend using the instance identifier), and the version of the pipeline code/transformations.

    ShortIdentifies EMR instance & pipeline version the resource came from
    Comments

    In the provenance resource, this corresponds to Provenance.entity.what[x]. The exact use of the source (and the implied Provenance.entity.role) is left to implementer discretion. Only one nominated source is allowed; for additional provenance details, a full Provenance resource should be used.

    This element can be used to indicate where the current master source of a resource that has a canonical URL if the resource is no longer hosted at the canonical URL.

    Control0..1
    Typeuri
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Must Supporttrue
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    16. Basic.meta.profile
    Definition

    A list of profiles (references to StructureDefinition resources) that this resource claims to conform to. The URL is a reference to StructureDefinition.url.

    ShortProfiles this resource claims to conform to
    Comments

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

    Control0..*
    Typecanonical(StructureDefinition)
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    18. Basic.meta.security
    Definition

    Security labels applied to this resource. These tags connect specific resources to the overall security policy and infrastructure.

    ShortSecurity Labels applied to this resource
    Comments

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

    Control0..*
    BindingUnless not suitable, these codes SHALL be taken from All Security Labels
    (extensible to http://hl7.org/fhir/ValueSet/security-labels|4.0.1)

    Security Labels from the Healthcare Privacy and Security Classification System.

    TypeCoding
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    20. Basic.meta.tag
    Definition

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

    ShortTags applied to this resource
    Comments

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

    Control0..*
    BindingFor example codes, see CommonTags
    (example to http://hl7.org/fhir/ValueSet/common-tags|4.0.1)

    Codes that represent various types of tags, commonly workflow-related; e.g. "Needs review by Dr. Jones".

    TypeCoding
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    22. Basic.implicitRules
    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. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

    ShortA set of rules under which this content was created
    Comments

    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. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

    Control0..1
    Typeuri
    Is Modifiertrue because This element is labeled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    24. Basic.language
    Definition

    The base language in which the resource is written.

    ShortLanguage of the resource content
    Comments

    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).

    Control0..1
    BindingThe codes SHOULD be taken from CommonLanguages
    (preferred to http://hl7.org/fhir/ValueSet/languages|4.0.1)

    A human language.

    Additional BindingsPurpose
    AllLanguagesMax Binding
    Typecode
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summaryfalse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    26. Basic.text
    Definition

    A human-readable narrative summary of the PolarisCoreAppState resource for human interpretation.

    ShortNarrative
    Comments

    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 information is added later.

    Control0..1
    TypeNarrative
    Is Modifierfalse
    Must Supporttrue
    Summaryfalse
    Alternate Namesnarrative, html, xhtml, display
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    28. Basic.contained
    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.

    ShortContained, inline Resources
    Comments

    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. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

    Control0..*
    TypeResource
    Is Modifierfalse
    Summaryfalse
    Alternate Namesinline resources, anonymous resources, contained resources
    30. Basic.extension
    Definition

    Contains the application state values using type-specific extensions (string, boolean, etc.).

    ShortThe actual state value(s) - can have an arbitrary number of state values
    Comments

    Different extension types support different value data types.

    Control1..*
    TypeExtension
    Is Modifierfalse
    Must Supporttrue
    Summaryfalse
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    32. Basic.extension.id
    Definition

    Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

    ShortUnique id for inter-element referencing
    Control0..1
    Typestring
    Is Modifierfalse
    XML FormatIn the XML format, this property is represented as an attribute.
    Summaryfalse
    34. Basic.extension.extension
    Definition

    May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

    ShortAdditional content defined by implementations
    Comments

    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.

    Control0..*
    TypeExtension
    Is Modifierfalse
    Summaryfalse
    Alternate Namesextensions, user content
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    SlicingThis element introduces a set of slices on Basic.extension.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 36. Basic.extension.url
      Definition

      Identifies which type of value extension is being used (string, boolean, etc.).

      ShortExtension type URL
      Comments

      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.

      Control1..1
      Typeuri
      Is Modifierfalse
      Must Supporttrue
      XML FormatIn the XML format, this property is represented as an attribute.
      Summaryfalse
      38. Basic.extension.value[x]
      Definition

      Value of extension - must be one of a constrained set of the data types (see Extensibility for a list).

      ShortValue of extension
      Control0..1
      TypeChoice of: base64Binary, boolean, canonical, code, date, dateTime, decimal, id, instant, integer, markdown, oid, positiveInt, string, time, unsignedInt, uri, url, uuid, Address, Age, Annotation, Attachment, CodeableConcept, Coding, ContactPoint, Count, Distance, Duration, HumanName, Identifier, Money, Period, Quantity, Range, Ratio, Reference, SampledData, Signature, Timing, ContactDetail, Contributor, DataRequirement, Expression, ParameterDefinition, RelatedArtifact, TriggerDefinition, UsageContext, Dosage, Meta
      [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      40. Basic.modifierExtension
      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 and/or the understanding of the containing element's descendants. Usually modifier elements provide negation or qualification. 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.

      Modifier extensions SHALL NOT change the meaning of any elements on Resource or DomainResource (including cannot change the meaning of modifierExtension itself).

      ShortExtensions that cannot be ignored
      Comments

      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.

      Control0..*
      TypeExtension
      Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
      Summaryfalse
      Requirements

      Modifier extensions allow for extensions that cannot be safely ignored to be clearly distinguished from the vast majority of extensions which can be safely ignored. This promotes interoperability by eliminating the need for implementers to prohibit the presence of extensions. For further information, see the definition of modifier extensions.

      Alternate Namesextensions, user content
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      42. Basic.identifier
      Definition

      Optional identifier for this application state entry.

      ShortBusiness identifier for app state
      Comments

      Most app state entries are identified by their code and subject rather than explicit identifiers.

      NoteThis is a business identifier, not a resource identifier (see discussion)
      Control0..1
      TypeIdentifier
      Is Modifierfalse
      Must Supporttrue
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      44. Basic.code
      Definition

      Identifies what kind of application state this represents and which application namespace it belongs to.

      ShortType and namespace of application state
      Comments

      The code acts as both a type discriminator and namespace identifier for the state data.

      Control1..1
      BindingFor example codes, see BasicResourceTypes
      (example to http://hl7.org/fhir/ValueSet/basic-resource-type|4.0.1)

      Codes for identifying types of resources not yet defined by FHIR.

      TypeCodeableConcept
      Is Modifiertrue because This element determines what kind of resource is being represented which drives the meaning of all of the other elements.
      Must Supporttrue
      Summarytrue
      Requirements

      Must be able to distinguish different types of Basic resources.

      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      46. Basic.code.id
      Definition

      Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

      ShortUnique id for inter-element referencing
      Control0..1
      Typestring
      Is Modifierfalse
      XML FormatIn the XML format, this property is represented as an attribute.
      Summaryfalse
      48. Basic.code.extension
      Definition

      May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

      ShortAdditional content defined by implementations
      Comments

      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.

      Control0..*
      TypeExtension
      Is Modifierfalse
      Summaryfalse
      Alternate Namesextensions, user content
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      SlicingThis element introduces a set of slices on Basic.code.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
      • value @ url
      • 50. Basic.code.coding
        Definition

        The coded representation of the application state type.

        ShortCoded type of state
        Comments

        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.

        Control1..1
        TypeCoding
        Is Modifierfalse
        Must Supporttrue
        Summarytrue
        Requirements

        Allows for alternative encodings within a code system, and translations to other code systems.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        app-state-system-inv: AppState coding.system must match Polaris CodeSystem URL rules. (system.matches('https://fhir.apps.health/CodeSystem/[a-zA-Z0-9.-]+-app-state'))
        52. Basic.code.coding.id
        Definition

        Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

        ShortUnique id for inter-element referencing
        Control0..1
        Typestring
        Is Modifierfalse
        XML FormatIn the XML format, this property is represented as an attribute.
        Summaryfalse
        54. Basic.code.coding.extension
        Definition

        May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        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.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        SlicingThis element introduces a set of slices on Basic.code.coding.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
        • value @ url
        • 56. Basic.code.coding.system
          Definition

          Must follow pattern: https://fhir.apps.health/CodeSystem/[app-name]-app-state

          ShortApplication-specific CodeSystem URL
          Comments

          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 reference to some definition that establishes the system clearly and unambiguously.

          Control1..1
          Typeuri
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Summarytrue
          Requirements

          Need to be unambiguous about the source of the definition of the symbol.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          58. Basic.code.coding.version
          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.

          ShortVersion of the system - if relevant
          Comments

          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.

          NoteThis is a business version Id, not a resource version Id (see discussion)
          Control0..1
          Typestring
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          60. Basic.code.coding.code
          Definition

          The specific type of state within the application's namespace.

          ShortSpecific state type code
          Control1..1
          Typecode
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Summarytrue
          Requirements

          Need to refer to a particular code in the system.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          62. Basic.code.coding.display
          Definition

          A representation of the meaning of the code in the system, following the rules of the system.

          ShortHuman-readable state type name
          Control0..1
          Typestring
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Summarytrue
          Requirements

          Need to be able to carry a human-readable meaning of the code for readers that do not know the system.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          64. Basic.code.coding.userSelected
          Definition

          Indicates that this coding was chosen by a user directly - e.g. off a pick list of available items (codes or displays).

          ShortIf this coding was chosen directly by the user
          Comments

          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.

          Control0..1
          Typeboolean
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Summarytrue
          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.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          66. Basic.code.text
          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.

          ShortPlain text description of state type
          Comments

          Very often the text is the same as a displayName of one of the codings.

          Control0..1
          Typestring
          Is Modifierfalse
          Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
          Must Supporttrue
          Summarytrue
          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.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          68. Basic.subject
          Definition

          The FHIR resource (Patient, PractitionerRole, Organization, etc.) that this application state is associated with.

          ShortResource this state is associated with
          Comments

          Application state is always linked to a specific resource for context.

          Control1..1
          TypeReference(Polaris Patient Core, Polaris PractitionerRole Core, Polaris Organization Core)
          Is Modifierfalse
          Summarytrue
          Requirements

          Needed for partitioning the resource by Patient.

          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          70. Basic.subject.id
          Definition

          Unique id for the element within a resource (for internal references). This may be any string value that does not contain spaces.

          ShortUnique id for inter-element referencing
          Control0..1
          Typestring
          Is Modifierfalse
          XML FormatIn the XML format, this property is represented as an attribute.
          Summaryfalse
          72. Basic.subject.extension
          Definition

          May be used to represent additional information that is not part of the basic definition of the element. 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 can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

          ShortAdditional content defined by implementations
          Comments

          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.

          Control0..*
          TypeExtension
          Is Modifierfalse
          Summaryfalse
          Alternate Namesextensions, user content
          Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
          ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
          SlicingThis element introduces a set of slices on Basic.subject.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
          • value @ url
          • 74. Basic.subject.reference
            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.

            ShortReference to the associated resource
            Comments

            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.

            Control0..1
            This element is affected by the following invariants: ref-1
            Typestring
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            76. Basic.subject.type
            Definition

            The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

            The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

            ShortType of resource referenced
            Comments

            This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

            Control0..1
            BindingUnless not suitable, these codes SHALL be taken from ResourceType
            (extensible to http://hl7.org/fhir/ValueSet/resource-types|4.0.1)

            Aa resource (or, for logical models, the URI of the logical model).

            Typeuri
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            78. Basic.subject.identifier
            Definition

            An identifier for the target resource. This is used when there is no way to reference the other resource directly, either because the entity it represents 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.

            ShortLogical reference, when literal reference is not known
            Comments

            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.

            Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

            NoteThis is a business identifier, not a resource identifier (see discussion)
            Control0..1
            TypeIdentifier
            Is Modifierfalse
            Summarytrue
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            80. Basic.subject.display
            Definition

            Plain text narrative that identifies the resource in addition to the resource reference.

            ShortDisplay name of referenced resource
            Comments

            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.

            Control0..1
            Typestring
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Must Supporttrue
            Summarytrue
            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            82. Basic.created
            Definition

            Identifies when the resource was first created.

            ShortWhen created
            Control0..1
            Typedate
            Is Modifierfalse
            Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
            Summarytrue
            Requirements

            Allows ordering resource instances by time.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            84. Basic.author
            Definition

            Indicates who was responsible for creating the resource instance.

            ShortWho created
            Control0..1
            TypeReference(Practitioner, PractitionerRole, Patient, RelatedPerson, Organization)
            Is Modifierfalse
            Summarytrue
            Requirements

            Needed for partitioning the resource.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))