NZ Shared Digital Health Record API
0.5.0 - ballot

NZ Shared Digital Health Record API - Local Development build (v0.5.0) built by the FHIR (HL7® FHIR® Standard) Build Tools. See the Directory of published versions

Resource Profile: SDHREncounter - Detailed Descriptions

Draft as of 2025-06-10

Definitions for the SDHREncounter resource profile.

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

0. Encounter
Definition

An interaction between a patient and healthcare provider(s) for the purpose of providing healthcare service(s) or assessing the health status of a patient.

ShortAn interaction during which services are provided to the patient
Control0..*
Is Modifierfalse
Summaryfalse
Alternate NamesVisit
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. Encounter.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..01
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()))
4. Encounter.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..01
BindingThe codes SHOULD be taken from CommonLanguageshttp://hl7.org/fhir/ValueSet/languages
(preferred to http://hl7.org/fhir/ValueSet/languages)

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()))
6. Encounter.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..0*
TypeResource
Is Modifierfalse
Summaryfalse
Alternate Namesinline resources, anonymous resources, contained resources
8. Encounter.extension
Definition

An Extension


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.

ShortExtensionAdditional 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 Encounter.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 10. Encounter.extension:ClientLastUpdated
    Slice NameClientLastUpdated
    Definition

    Extension to record the last time a resource was updated by the source system. When consuming applications are writing data to the SDHR API they can use this extension to record the LastUpdated timestamp in their system

    ShortClient Last Updated
    Control0..1
    This element is affected by the following invariants: ele-1
    TypeExtension(Client Last Updated) (Extension Type: dateTime)
    Is Modifierfalse
    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())
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    12. Encounter.modifierExtension
    Definition

    An Extension


    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).

    ShortExtensionExtensions 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..0*
    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())
    14. Encounter.identifier
    Definition

    A local identifier MAY be added to this section. This can be used to correlate the SDHR resource with a local system identifier to perform updates.


    Identifier(s) by which this encounter is known.

    ShortA local identifier MAY be added to this section. If used, system MUST be specified.Identifier(s) by which this encounter is known
    NoteThis is a business identifier, not a resource identifier (see discussion)
    Control10..*
    TypeIdentifier
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    16. Encounter.identifier.use
    Definition

    The purpose of this identifier.

    ShortThe local identifier use SHOULD be set to secondary, where the SDHR resource id is considered the primary identifier.usual | official | temp | secondary | old (If known)
    Comments

    Applications can assume that an identifier is permanent unless it explicitly says that it is temporary.

    Control0..1
    BindingThe codes SHALL be taken from IdentifierUsehttp://hl7.org/fhir/ValueSet/identifier-use|4.0.1
    (required to http://hl7.org/fhir/ValueSet/identifier-use|4.0.1)

    Identifies the purpose for this identifier, if known .

    Typecode
    Is Modifiertrue because This is labeled as "Is Modifier" because applications should not mistake a temporary id for a permanent one.
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Requirements

    Allows the appropriate identifier for a particular context of use to be selected from among a set of identifiers.

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

    Establishes the namespace for the value - that is, a URL that describes a set values that are unique.

    ShortSystem for the local identifier. This MUST be consistent per PMS/Health ApplicationThe namespace for the identifier value
    Comments

    Identifier.system is always case sensitive.

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

    Example<br/><b>General</b>:http://www.acme.com/identifiers/patient <br/><b>Local Identifier System</b>:https://fhir.example.co.nz
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    20. Encounter.identifier.value
    Definition

    The portion of the identifier typically relevant to the user and which is unique within the context of the system.

    ShortThe actual local identifier value, e.g. ec2d6cad-1e19-46ee-accf-dc460a680710The value that is unique
    Comments

    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. Identifier.value is to be treated as case sensitive unless knowledge of the Identifier.system allows the processer to be confident that non-case-sensitive processing is safe.

    Control10..1
    Typestring
    Is Modifierfalse
    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
    Summarytrue
    Example<br/><b>General</b>:123456 <br/><b>Local Identifier Value</b>:ec2d6cad-1e19-46ee-accf-dc460a680710
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    22. Encounter.status
    Definition

    planned | arrived | triaged | in-progress | onleave | finished | cancelled +.

    Shortplanned | arrived | triaged | in-progress | onleave | finished | cancelled +
    Comments

    Note that internal business rules will determine the appropriate transitions that may occur between statuses (and also classes).

    Control1..1
    BindingThe codes SHALL be taken from EncounterStatushttp://hl7.org/fhir/ValueSet/encounter-status|4.0.1
    (required to http://hl7.org/fhir/ValueSet/encounter-status|4.0.1)

    Current state of the encounter.

    Typecode
    Is Modifiertrue because This element is labeled as a modifier because it is a status element that contains status entered-in-error which means that the resource should not be treated as valid
    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. Encounter.class
    Definition

    Concepts representing classification of patient encounter such as ambulatory (outpatient), inpatient, emergency, home health or others due to local variations.

    ShortClassification of patient encounter
    Control1..1
    BindingThe codes SHALL be taken from Unless not suitable, these codes SHALL be taken from ValueSet for EncounterStatushttp://terminology.hl7.org/ValueSet/v3-ActEncounterCode
    (required to https://fhir-ig.digital.health.nz/sdhr/ValueSet/sdhr-encounter-class-valueset)
    TypeCoding
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    26. Encounter.subject
    Definition

    The patient or group present at the encounter.

    ShortThe patient or group present at the encounter
    Comments

    While the encounter is always about the patient, the patient might not actually be known in all contexts of use, and there may be a group of patients that could be anonymous (such as in a group therapy for Alcoholics Anonymous - where the recording of the encounter could be used for billing on the number of people/staff and not important to the context of the specific patients) or alternately in veterinary care a herd of sheep receiving treatment (where the animals are not individually tracked).

    Control10..1
    TypeReference(Patient, Group)
    Is Modifierfalse
    Summarytrue
    Alternate Namespatient
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    28. Encounter.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.

    ShortMust be an absolute URL reference to the patient on the NHI system. See constraints for details.Literal 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.

    Control10..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
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    nhi-url-format: Reference must be an NHI Patient URL with format https://api.hip.digital.health.nz/fhir/nhi/v1/Patient/ZZZ1111 or ZZZ11AA (matches('^https://api.hip.digital.health.nz/fhir/nhi/v1/Patient/[A-Z]{3}([0-9]{4}|[0-9]{2}[A-Z]{2})$'))
    30. Encounter.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 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.

    Control10..1
    BindingUnless not suitable, these codes SHALL be taken from ResourceTypehttp://hl7.org/fhir/ValueSet/resource-types
    (extensible to http://hl7.org/fhir/ValueSet/resource-types)

    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
    Summarytrue
    Pattern ValuePatient
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    32. Encounter.participant
    Definition

    The list of people responsible for providing the service.

    ShortList of participants involved in the encounter
    Control10..*
    TypeBackboneElement
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    34. Encounter.participant.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..01
    Typestring
    Is Modifierfalse
    XML FormatIn the XML format, this property is represented as an attribute.
    Summaryfalse
    36. Encounter.participant.extension
    Definition

    An Extension


    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.

    ShortExtensionAdditional 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..0*
    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())
    38. Encounter.participant.modifierExtension
    Definition

    An Extension


    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 in which it is contained 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 can 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).

    ShortExtensionExtensions that cannot be ignored even if unrecognized
    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..0*
    TypeExtension
    Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the element that contains them
    Summarytrue
    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, modifiers
    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())
    40. Encounter.participant.individual
    Definition

    Persons involved in the encounter other than the patient.

    ShortPersons involved in the encounter other than the patient
    Control10..1
    TypeReference(Practitioner, PractitionerRole, RelatedPerson)
    Is Modifierfalse
    Summarytrue
    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
    42. Encounter.participant.individual.extension
    Definition

    An Extension


    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.

    ShortExtensionAdditional 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..0*
    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 Encounter.participant.individual.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 44. Encounter.participant.individual.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.

      ShortMust be an absolute URL reference to the practitioner on the HPI system. See constraints for details.Literal 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
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      hpi-url-format: Reference must be an HPI Practitioner URL with format https://api.hip.digital.health.nz/fhir/hpi/v1/Practitioner/11AAAA (matches('^https://api.hip.digital.health.nz/fhir/hpi/v1/Practitioner/[0-9]{2}[A-Z]{4}$'))
      46. Encounter.participant.individual.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 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
      (extensible to http://hl7.org/fhir/ValueSet/resource-types)

      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
      Summarytrue
      Pattern ValuePractitioner
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      48. Encounter.participant.individual.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..01
      TypeIdentifier
      Is Modifierfalse
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      50. Encounter.period
      Definition

      The start and end time of the encounter.

      ShortThe start and end time of the encounter
      Comments

      If not (yet) known, the end of the Period may be omitted.

      Control10..1
      TypePeriod
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      52. Encounter.account
      Definition

      The set of accounts that may be used for billing for this Encounter.

      ShortThe set of accounts that may be used for billing for this Encounter
      Comments

      The billing system may choose to allocate billable items associated with the Encounter to different referenced Accounts based on internal business rules.

      Control0..0*
      TypeReference(Account)
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      54. Encounter.hospitalization
      Definition

      Details about the admission to a healthcare service.

      ShortDetails about the admission to a healthcare service
      Comments

      An Encounter may cover more than just the inpatient stay. Contexts such as outpatients, community clinics, and aged care facilities are also included.

      The duration recorded in the period of this encounter covers the entire scope of this hospitalization record.

      Control0..01
      TypeBackboneElement
      Is Modifierfalse
      Summaryfalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))