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.

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.

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.

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).

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.

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.

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

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

Current state of the encounter.

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

Classification of the encounter.

STU3: Encounter.meta additional types (Meta) additional types from child elements (lastUpdated, profile, security, tag, versionId)

Element Encounter.meta is mapped to FHIR R4B element Encounter.meta as SourceIsBroaderThanTarget. The mappings for Encounter.meta do not cover the following types: Meta. The mappings for Encounter.meta do not cover the following types based on type expansion: lastUpdated, profile, security, tag, versionId.

STU3: Encounter.text additional types (Narrative) additional types from child elements (div, status)

Element Encounter.text is mapped to FHIR R4B element Encounter.text as SourceIsBroaderThanTarget. The mappings for Encounter.text do not cover the following types: Narrative. The mappings for Encounter.text do not cover the following types based on type expansion: div, status. Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded in formation is added later.

STU3: Encounter.identifier additional types (Identifier) additional types from child elements (assigner, period, system, type, use, value)

Element Encounter.identifier is mapped to FHIR R4B element Encounter.identifier as SourceIsBroaderThanTarget. The mappings for Encounter.identifier do not cover the following types: Identifier. The mappings for Encounter.identifier do not cover the following types based on type expansion: assigner, period, system, type, use, value.

STU3: Encounter.statusHistory.period additional types (Period) additional types from child elements (end, start)

Element Encounter.statusHistory.period is mapped to FHIR R4B element Encounter.statusHistory.period as SourceIsBroaderThanTarget. The mappings for Encounter.statusHistory.period do not cover the following types: Period. The mappings for Encounter.statusHistory.period do not cover the following types based on type expansion: end, start.

STU3: Encounter.classHistory.period additional types (Period) additional types from child elements (end, start)

Element Encounter.classHistory.period is mapped to FHIR R4B element Encounter.classHistory.period as SourceIsBroaderThanTarget. The mappings for Encounter.classHistory.period do not cover the following types: Period. The mappings for Encounter.classHistory.period do not cover the following types based on type expansion: end, start.

STU3: Encounter.subject additional types from child elements (display, identifier, reference)

Element Encounter.subject is mapped to FHIR R4B element Encounter.subject as SourceIsBroaderThanTarget. The mappings for Encounter.subject do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.subject with unmapped reference targets: Group, Patient. While the encounter is always about the patient, the patient may 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).

STU3: Encounter.episodeOfCare additional types from child elements (display, identifier, reference)

Element Encounter.episodeOfCare is mapped to FHIR R4B element Encounter.episodeOfCare as SourceIsBroaderThanTarget. The mappings for Encounter.episodeOfCare do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.episodeOfCare with unmapped reference targets: EpisodeOfCare.

STU3: Encounter.incomingReferral additional types from child elements (display, identifier, reference)

Element Encounter.incomingReferral is mapped to FHIR R4B element Encounter.basedOn as RelatedTo. The mappings for Encounter.incomingReferral do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.incomingReferral with unmapped reference targets: ReferralRequest.

STU3: Encounter.participant.period additional types (Period) additional types from child elements (end, start)

Element Encounter.participant.period is mapped to FHIR R4B element Encounter.participant.period as SourceIsBroaderThanTarget. The mappings for Encounter.participant.period do not cover the following types: Period. The mappings for Encounter.participant.period do not cover the following types based on type expansion: end, start.

STU3: Encounter.participant.individual additional types from child elements (display, identifier, reference)

Element Encounter.participant.individual is mapped to FHIR R4B element Encounter.participant.individual as SourceIsBroaderThanTarget. The mappings for Encounter.participant.individual do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.participant.individual with unmapped reference targets: Practitioner, RelatedPerson.

STU3: Encounter.appointment additional types from child elements (display, identifier, reference)

Element Encounter.appointment is mapped to FHIR R4B element Encounter.appointment as RelatedTo. The mappings for Encounter.appointment do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.appointment with unmapped reference targets: Appointment.

STU3: Encounter.period additional types (Period) additional types from child elements (end, start)

Element Encounter.period is mapped to FHIR R4B element Encounter.period as SourceIsBroaderThanTarget. The mappings for Encounter.period do not cover the following types: Period. The mappings for Encounter.period do not cover the following types based on type expansion: end, start. If not (yet) known, the end of the Period may be omitted.

STU3: Encounter.diagnosis.condition additional types from child elements (display, identifier, reference)

Element Encounter.diagnosis.condition is mapped to FHIR R4B element Encounter.diagnosis.condition as SourceIsBroaderThanTarget. The mappings for Encounter.diagnosis.condition do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.diagnosis.condition with unmapped reference targets: Condition, Procedure. For systems that need to know which was the primary diagnosis, these will be marked with the standard extension primaryDiagnosis (which is a sequence value rather than a flag, 1 = primary diagnosis).

STU3: Encounter.account additional types from child elements (display, identifier, reference)

Element Encounter.account is mapped to FHIR R4B element Encounter.account as SourceIsBroaderThanTarget. The mappings for Encounter.account do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.account with unmapped reference targets: Account. The billing system may choose to allocate billable items associated with the Encounter to different referenced Accounts based on internal business rules.

STU3: Encounter.hospitalization.preAdmissionIdentifier additional types (Identifier) additional types from child elements (assigner, period, system, type, use, value)

Element Encounter.hospitalization.preAdmissionIdentifier is mapped to FHIR R4B element Encounter.hospitalization.preAdmissionIdentifier as SourceIsBroaderThanTarget. The mappings for Encounter.hospitalization.preAdmissionIdentifier do not cover the following types: Identifier. The mappings for Encounter.hospitalization.preAdmissionIdentifier do not cover the following types based on type expansion: assigner, period, system, type, use, value.

STU3: Encounter.hospitalization.origin additional types from child elements (display, identifier, reference)

Element Encounter.hospitalization.origin is mapped to FHIR R4B element Encounter.hospitalization.origin as SourceIsBroaderThanTarget. The mappings for Encounter.hospitalization.origin do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.hospitalization.origin with unmapped reference targets: Location.

STU3: Encounter.hospitalization.destination additional types from child elements (display, identifier, reference)

Element Encounter.hospitalization.destination is mapped to FHIR R4B element Encounter.hospitalization.destination as SourceIsBroaderThanTarget. The mappings for Encounter.hospitalization.destination do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.hospitalization.destination with unmapped reference targets: Location.

STU3: Encounter.location.location additional types from child elements (display, identifier, reference)

Element Encounter.location.location is mapped to FHIR R4B element Encounter.location.location as SourceIsBroaderThanTarget. The mappings for Encounter.location.location do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.location.location with unmapped reference targets: Location.

STU3: Encounter.location.period additional types (Period) additional types from child elements (end, start)

Element Encounter.location.period is mapped to FHIR R4B element Encounter.location.period as SourceIsBroaderThanTarget. The mappings for Encounter.location.period do not cover the following types: Period. The mappings for Encounter.location.period do not cover the following types based on type expansion: end, start.

STU3: Encounter.serviceProvider additional types from child elements (display, identifier, reference)

Element Encounter.serviceProvider is mapped to FHIR R4B element Encounter.serviceProvider as SourceIsBroaderThanTarget. The mappings for Encounter.serviceProvider do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.serviceProvider with unmapped reference targets: Organization.

STU3: Encounter.partOf additional types from child elements (display, identifier, reference)

Element Encounter.partOf is mapped to FHIR R4B element Encounter.partOf as SourceIsBroaderThanTarget. The mappings for Encounter.partOf do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.partOf with unmapped reference targets: Encounter. This is also used for associating a child's encounter back to the mother's encounter.

Refer to the Notes section in the Patient resource for further details.

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.

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

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

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.

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

An Extension

STU3: Encounter.meta additional types (Meta) additional types from child elements (lastUpdated, profile, security, tag, versionId)

Element Encounter.meta is mapped to FHIR R4B element Encounter.meta as SourceIsBroaderThanTarget. The mappings for Encounter.meta do not cover the following types: Meta. The mappings for Encounter.meta do not cover the following types based on type expansion: lastUpdated, profile, security, tag, versionId.

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.

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.

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

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.

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.

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.

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

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.

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

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.

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.

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.

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.

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.

The base language in which the resource is written.

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).

IETF language tag

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.

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.

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

An Extension

STU3: Encounter.text additional types (Narrative) additional types from child elements (div, status)

Element Encounter.text is mapped to FHIR R4B element Encounter.text as SourceIsBroaderThanTarget. The mappings for Encounter.text do not cover the following types: Narrative. The mappings for Encounter.text do not cover the following types based on type expansion: div, status. Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded in formation is added later.

The status of the narrative - whether it's entirely generated (from just the defined data or the extensions too), or whether a human authored it and it may contain additional data.

The actual narrative content, a stripped down version of XHTML.

The contents of the html element are an XHTML fragment containing only the basic html formatting elements described in chapters 7-11 and 15 of the HTML 4.0 standard, <a> elements (either name or href), images and internally contained stylesheets. The XHTML content SHALL NOT contain a head, a body, external stylesheet references, scripts, forms, base/link/xlink, frames, iframes and objects.

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.

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.

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.

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.

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).

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.

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.

Identifier(s) by which this encounter is known.

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

An Extension

STU3: Encounter.identifier additional types (Identifier) additional types from child elements (assigner, period, system, type, use, value)

Element Encounter.identifier is mapped to FHIR R4B element Encounter.identifier as SourceIsBroaderThanTarget. The mappings for Encounter.identifier do not cover the following types: Identifier. The mappings for Encounter.identifier do not cover the following types based on type expansion: assigner, period, system, type, use, value.

The purpose of this identifier.

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

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

A coded type for the identifier that can be used to determine which identifier to use for a specific purpose.

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

Allows users to make use of identifiers when the identifier system is not known.

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

Identifier.system is always case sensitive.

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.

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

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.

Time period during which identifier is/was valid for use.

Organization that issued/manages the identifier.

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

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

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

Current state of the encounter.

The status history permits the encounter resource to contain the status history without needing to read through the historical versions of the resource, or even have the server store them.

The current status is always found in the current version of the resource, not the status history.

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

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.

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.

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).

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.

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.

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

Current state of the encounter.

The time that the episode was in the specified status.

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

An Extension

STU3: Encounter.statusHistory.period additional types (Period) additional types from child elements (end, start)

Element Encounter.statusHistory.period is mapped to FHIR R4B element Encounter.statusHistory.period as SourceIsBroaderThanTarget. The mappings for Encounter.statusHistory.period do not cover the following types: Period. The mappings for Encounter.statusHistory.period do not cover the following types based on type expansion: end, start.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

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

Classification of the encounter.

The class history permits the tracking of the encounters transitions without needing to go through the resource history. This would be used for a case where an admission starts of as an emergency encounter, then transitions into an inpatient scenario. Doing this and not restarting a new encounter ensures that any lab/diagnostic results can more easily follow the patient and not require re-processing and not get lost or cancelled during a kind of discharge from emergency to inpatient.

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

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.

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.

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).

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.

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.

inpatient | outpatient | ambulatory | emergency +.

Classification of the encounter.

The time that the episode was in the specified class.

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

An Extension

STU3: Encounter.classHistory.period additional types (Period) additional types from child elements (end, start)

Element Encounter.classHistory.period is mapped to FHIR R4B element Encounter.classHistory.period as SourceIsBroaderThanTarget. The mappings for Encounter.classHistory.period do not cover the following types: Period. The mappings for Encounter.classHistory.period do not cover the following types based on type expansion: end, start.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

Specific type of encounter (e.g. e-mail consultation, surgical day-care, skilled nursing, rehabilitation).

Since there are many ways to further classify encounters, this element is 0..*.

A specific code indicating type of service provided

Broad categorization of the service that is to be provided (e.g. cardiology).

Broad categorization of the service that is to be provided.

Indicates the urgency of the encounter.

Indicates the urgency of the encounter.

The patient or group present at the encounter.

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).

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

An Extension

STU3: Encounter.subject additional types from child elements (display, identifier, reference)

Element Encounter.subject is mapped to FHIR R4B element Encounter.subject as SourceIsBroaderThanTarget. The mappings for Encounter.subject do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.subject with unmapped reference targets: Group, Patient. While the encounter is always about the patient, the patient may 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).

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.

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.

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).

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.

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.

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).

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

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.

Where a specific encounter should be classified as a part of a specific episode(s) of care this field should be used. This association can facilitate grouping of related encounters together for a specific purpose, such as government reporting, issue tracking, association via a common problem. The association is recorded on the encounter as these are typically created after the episode of care and grouped on entry rather than editing the episode of care to append another encounter to it (the episode of care could span years).

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

An Extension

STU3: Encounter.episodeOfCare additional types from child elements (display, identifier, reference)

Element Encounter.episodeOfCare is mapped to FHIR R4B element Encounter.episodeOfCare as SourceIsBroaderThanTarget. The mappings for Encounter.episodeOfCare do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.episodeOfCare with unmapped reference targets: EpisodeOfCare.

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.

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.

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).

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.

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.

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).

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

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.

The request this encounter satisfies (e.g. incoming referral or procedure request).

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

An Extension

STU3: Encounter.incomingReferral additional types from child elements (display, identifier, reference)

Element Encounter.incomingReferral is mapped to FHIR R4B element Encounter.basedOn as RelatedTo. The mappings for Encounter.incomingReferral do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.incomingReferral with unmapped reference targets: ReferralRequest.

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.

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.

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).

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.

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.

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).

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

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.

The list of people responsible for providing the service.

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

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.

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.

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).

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.

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.

Role of participant in encounter.

The participant type indicates how an individual participates in an encounter. It includes non-practitioner participants, and for practitioners this is to describe the action type in the context of this encounter (e.g. Admitting Dr, Attending Dr, Translator, Consulting Dr). This is different to the practitioner roles which are functional roles, derived from terms of employment, education, licensing, etc.

Role of participant in encounter.

The period of time that the specified participant participated in the encounter. These can overlap or be sub-sets of the overall encounter's period.

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

An Extension

STU3: Encounter.participant.period additional types (Period) additional types from child elements (end, start)

Element Encounter.participant.period is mapped to FHIR R4B element Encounter.participant.period as SourceIsBroaderThanTarget. The mappings for Encounter.participant.period do not cover the following types: Period. The mappings for Encounter.participant.period do not cover the following types based on type expansion: end, start.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

Persons involved in the encounter other than the patient.

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

An Extension

STU3: Encounter.participant.individual additional types from child elements (display, identifier, reference)

Element Encounter.participant.individual is mapped to FHIR R4B element Encounter.participant.individual as SourceIsBroaderThanTarget. The mappings for Encounter.participant.individual do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.participant.individual with unmapped reference targets: Practitioner, RelatedPerson.

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.

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.

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).

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.

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.

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).

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

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.

The appointment that scheduled this encounter.

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

An Extension

STU3: Encounter.appointment additional types from child elements (display, identifier, reference)

Element Encounter.appointment is mapped to FHIR R4B element Encounter.appointment as RelatedTo. The mappings for Encounter.appointment do not cover the following types based on type expansion: display, identifier, reference. The standard extension alternate-reference has been mapped as the representation of FHIR STU3 element Encounter.appointment with unmapped reference targets: Appointment.

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.

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.

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).

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.

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.

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).

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

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.

The start and end time of the encounter.

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

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

An Extension

STU3: Encounter.period additional types (Period) additional types from child elements (end, start)

Element Encounter.period is mapped to FHIR R4B element Encounter.period as SourceIsBroaderThanTarget. The mappings for Encounter.period do not cover the following types: Period. The mappings for Encounter.period do not cover the following types based on type expansion: end, start. If not (yet) known, the end of the Period may be omitted.

The start of the period. The boundary is inclusive.

If the low element is missing, the meaning is that the low boundary is not known.

The end of the period. If the end of the period is missing, it means no end was known or planned at the time the instance was created. The start may be in the past, and the end date in the future, which means that period is expected/planned to end at that time.

The high value includes any matching date/time. i.e. 2012-02-03T10:00:00 is in a period that has an end value of 2012-02-03.

Quantity of time the encounter lasted. This excludes the time during leaves of absence.

May differ from the time the Encounter.period lasted because of leave of absence.

Reason the encounter takes place, expressed as a code. For admissions, this can be used for a coded admission diagnosis.

For systems that need to know which was the primary diagnosis, these will be marked with the standard extension primaryDiagnosis (which is a sequence value rather than a flag, 1 = primary diagnosis).

Reason why the encounter takes place.

Reason the encounter takes place, expressed as a code. For admissions, this can be used for a coded admission diagnosis.

For systems that need to know which was the primary diagnosis, these will be marked with the standard extension primaryDiagnosis (which is a sequence value rather than a flag, 1 = primary diagnosis).

The list of diagnosis relevant to this encounter.

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

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.

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.