A persistent identifier for the bundle that won't change as a bundle is copied from server to server.

Persistent identity generally only matters for batches of type Document, Message, and Collection. It would not normally be populated for search and history results and servers ignore Bundle.identifier when processing batches and transactions. For Documents the .identifier SHALL be populated such that the .identifier is globally unique.

If a set of search matches, this is the total number of entries of type 'match' across all pages in the search. It does not include search.mode = 'include' or 'outcome' entries and it does not provide a count of the number of entries in the Bundle.

Only used if the bundle is a search result set. The total does not include resources such as OperationOutcome and included resources, only the total number of matching resources.

A name which details the functional use for this link - see http://www.iana.org/assignments/link-relations/link-relations.xhtml#link-relations-1.

Note that FHIR strings SHALL NOT exceed 1MB in size

The reference details for the link.

see http://en.wikipedia.org/wiki/Uniform_resource_identifier

A series of links that provide context to this entry.

The Absolute URL for the resource. The fullUrl SHALL NOT disagree with the id in the resource - i.e. if the fullUrl is not a urn:uuid, the URL shall be version-independent URL consistent with the Resource.id. The fullUrl is a version independent reference to the resource. The fullUrl element SHALL have a value except that:

• fullUrl can be empty on a POST (although it does not need to when specifying a temporary id for reference in the bundle)
• Results from operations might involve resources that are not identified.

fullUrl might not be unique in the context of a resource. Note that since FHIR resources do not need to be served through the FHIR API, the fullURL might be a URN or an absolute URL that does not end with the logical id of the resource (Resource.id). However, but if the fullUrl does look like a RESTful server URL (e.g. meets the regex, then the 'id' portion of the fullUrl SHALL end with the Resource.id.

Note that the fullUrl is not the same as the canonical URL - it's an absolute url for an endpoint serving the resource (these will happen to have the same value on the canonical server for the resource with the canonical URL).

The Resource for the entry. The purpose/meaning of the resource is determined by the Bundle.type.

Why this entry is in the result set - whether it's included as a match or because of an _include requirement, or to convey information or warning information about the search process.

There is only one mode. In some corner cases, a resource may be included because it is both a match and an include. In these circumstances, 'match' takes precedence.

When searching, the server's search ranking score for the entry.

Servers are not required to return a ranking score. 1 is most relevant, and 0 is least relevant. Often, search results are sorted by score, but the client may specify a different sort order.

See Patient Match for the EMPI search which relates to this element.

In a transaction or batch, this is the HTTP action to be executed for this entry. In a history bundle, this indicates the HTTP action that occurred.

Note that FHIR strings SHALL NOT exceed 1MB in size

The URL for this entry, relative to the root (the address to which the request is posted).

E.g. for a Patient Create, the method would be "POST" and the URL would be "Patient". For a Patient Update, the method would be PUT and the URL would be "Patient/[id]".

If the ETag values match, return a 304 Not Modified status. See the API documentation for "Conditional Read".

Note that FHIR strings SHALL NOT exceed 1MB in size

Only perform the operation if the last updated date matches. See the API documentation for "Conditional Read".

Note: This is intended for where precisely observed times are required, typically system logs etc., and not human-reported times - for them, see date and dateTime (which can be as precise as instant, but is not required to be) below. Time zone is always required

Only perform the operation if the Etag value matches. For more information, see the API section "Managing Resource Contention".

Note that FHIR strings SHALL NOT exceed 1MB in size

Instruct the server not to perform the create if a specified resource already exists. For further information, see the API documentation for "Conditional Create". This is just the query portion of the URL - what follows the "?" (not including the "?").

Note that FHIR strings SHALL NOT exceed 1MB in size

The status code returned by processing this entry. The status SHALL start with a 3 digit HTTP code (e.g. 404) and may contain the standard HTTP description associated with the status code.

Note that FHIR strings SHALL NOT exceed 1MB in size

The location header created by processing this operation, populated if the operation returns a location.

see http://en.wikipedia.org/wiki/Uniform_resource_identifier

The Etag for the resource, if the operation for the entry produced a versioned resource (see Resource Metadata and Versioning and Managing Resource Contention).

Etags match the Resource.meta.versionId. The ETag has to match the version id in the header if a resource is included.

The date/time that the resource was modified on the server.

This has to match the same time in the meta header (meta.lastUpdated) if a resource is included.

An OperationOutcome containing hints and warnings produced as part of processing this entry in a batch or transaction.

For a POST/PUT operation, this is the equivalent outcome that would be returned for prefer = operationoutcome - except that the resource is always returned whether or not the outcome is returned.

This outcome is not used for error responses in batch/transaction, only for hints and warnings. In a batch operation, the error will be in Bundle.entry.response, and for transaction, there will be a single OperationOutcome instead of a bundle in the case of an error.

A series of links that provide context to this entry.

The Absolute URL for the resource. The fullUrl SHALL NOT disagree with the id in the resource - i.e. if the fullUrl is not a urn:uuid, the URL shall be version-independent URL consistent with the Resource.id. The fullUrl is a version independent reference to the resource. The fullUrl element SHALL have a value except that:

• fullUrl can be empty on a POST (although it does not need to when specifying a temporary id for reference in the bundle)
• Results from operations might involve resources that are not identified.

fullUrl might not be unique in the context of a resource. Note that since FHIR resources do not need to be served through the FHIR API, the fullURL might be a URN or an absolute URL that does not end with the logical id of the resource (Resource.id). However, but if the fullUrl does look like a RESTful server URL (e.g. meets the regex, then the 'id' portion of the fullUrl SHALL end with the Resource.id.

Note that the fullUrl is not the same as the canonical URL - it's an absolute url for an endpoint serving the resource (these will happen to have the same value on the canonical server for the resource with the canonical URL).

Why this entry is in the result set - whether it's included as a match or because of an _include requirement, or to convey information or warning information about the search process.

There is only one mode. In some corner cases, a resource may be included because it is both a match and an include. In these circumstances, 'match' takes precedence.

When searching, the server's search ranking score for the entry.

Servers are not required to return a ranking score. 1 is most relevant, and 0 is least relevant. Often, search results are sorted by score, but the client may specify a different sort order.

See Patient Match for the EMPI search which relates to this element.

In a transaction or batch, this is the HTTP action to be executed for this entry. In a history bundle, this indicates the HTTP action that occurred.

Note that FHIR strings SHALL NOT exceed 1MB in size

The URL for this entry, relative to the root (the address to which the request is posted).

E.g. for a Patient Create, the method would be "POST" and the URL would be "Patient". For a Patient Update, the method would be PUT and the URL would be "Patient/[id]".

If the ETag values match, return a 304 Not Modified status. See the API documentation for "Conditional Read".

Note that FHIR strings SHALL NOT exceed 1MB in size

Only perform the operation if the last updated date matches. See the API documentation for "Conditional Read".

Note: This is intended for where precisely observed times are required, typically system logs etc., and not human-reported times - for them, see date and dateTime (which can be as precise as instant, but is not required to be) below. Time zone is always required

Only perform the operation if the Etag value matches. For more information, see the API section "Managing Resource Contention".

Note that FHIR strings SHALL NOT exceed 1MB in size

Instruct the server not to perform the create if a specified resource already exists. For further information, see the API documentation for "Conditional Create". This is just the query portion of the URL - what follows the "?" (not including the "?").

Note that FHIR strings SHALL NOT exceed 1MB in size

The status code returned by processing this entry. The status SHALL start with a 3 digit HTTP code (e.g. 404) and may contain the standard HTTP description associated with the status code.

Note that FHIR strings SHALL NOT exceed 1MB in size

The location header created by processing this operation, populated if the operation returns a location.

see http://en.wikipedia.org/wiki/Uniform_resource_identifier

The Etag for the resource, if the operation for the entry produced a versioned resource (see Resource Metadata and Versioning and Managing Resource Contention).

Etags match the Resource.meta.versionId. The ETag has to match the version id in the header if a resource is included.

The date/time that the resource was modified on the server.

This has to match the same time in the meta header (meta.lastUpdated) if a resource is included.

An OperationOutcome containing hints and warnings produced as part of processing this entry in a batch or transaction.

For a POST/PUT operation, this is the equivalent outcome that would be returned for prefer = operationoutcome - except that the resource is always returned whether or not the outcome is returned.

This outcome is not used for error responses in batch/transaction, only for hints and warnings. In a batch operation, the error will be in Bundle.entry.response, and for transaction, there will be a single OperationOutcome instead of a bundle in the case of an error.

Digital Signature - base64 encoded. XML-DSig or a JWT.

A Signature holds an electronic representation of a signature and its supporting context in a FHIR accessible form. The signature may either be a cryptographic type (XML DigSig or a JWS), which is able to provide non-repudiation proof, or it may be a graphical image that represents a signature or a signature process. This element allows capturing signatures on documents, messages, transactions or even search responses, to support content-authentication, non-repudiation or other business cases. This is primarily relevant where the bundle may travel through multiple hops or via other mechanisms where HTTPS non-repudiation is insufficient.

The signature could be created by the "author" of the bundle or by the originating device. Requirements around inclusion of a signature, verification of signatures and treatment of signed/non-signed bundles is implementation-environment specific.

The purpose of this identifier.

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

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

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

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

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.

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

A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times").

Period is not used for a duration (a measure of elapsed time). See Duration.

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.

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

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

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

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

Note that FHIR strings SHALL NOT exceed 1MB in size

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

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

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

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

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

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

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

Note that FHIR strings SHALL NOT exceed 1MB in size

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

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

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

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

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

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

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

Note that FHIR strings SHALL NOT exceed 1MB in size

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

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

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

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

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

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

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

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

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

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

Note that FHIR strings SHALL NOT exceed 1MB in size

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

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

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

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

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

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

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

Note that FHIR strings SHALL NOT exceed 1MB in size

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

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

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

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

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

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

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 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.

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).

The code specifying the level of confidentiality of the Composition.

The exact use of this element, and enforcement and issues related to highly sensitive documents are out of scope for the base specification, and delegated to implementation profiles (see security section). This element is labeled as a modifier because highly confidential documents must not be treated as if they are not.

The type of attestation the authenticator offers.

Indicates the level of authority of the attestation.

Note that FHIR strings SHALL NOT exceed 1MB in size

When the composition was attested by the party.

Identifies when the information in the composition was deemed accurate. (Things may have changed since then.).

Who attested the composition in the specified way.

Identifies who has taken on the responsibility for accuracy of the composition content.

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

Identifies the organization or group who is responsible for ongoing maintenance of and access to the composition/document information.

Identifies where to go to find the current version, where to report issues, etc.

This is useful when documents are derived from a composition - provides guidance for how to get the latest version of the document. This is optional because this is sometimes not known by the authoring system, and can be inferred by context. However, it is important that this information be known when working with a derived document, so providing a custodian is encouraged.

The type of relationship that this composition has with anther composition or document.

If this document appends another document, then the document cannot be fully understood without also accessing the referenced document.

This list of codes represents the main clinical acts, such as a colonoscopy or an appendectomy, being documented. In some cases, the event is inherent in the typeCode, such as a "History and Physical Report" in which the procedure being documented is necessarily a "History and Physical" act.

An event can further specialize the act inherent in the typeCode, such as where it is simply "Procedure Report" and the procedure was a "colonoscopy". If one or more eventCodes are included, they SHALL NOT conflict with the values inherent in the classCode, practiceSettingCode or typeCode, as such a conflict would create an ambiguous situation. This short list of codes is provided to be used as key words for certain types of queries.

The period of time covered by the documentation. There is no assertion that the documentation is a complete representation for this period, only that it documents events during this time.

A Period specifies a range of time; the context of use will specify whether the entire range applies (e.g. "the patient was an inpatient of the hospital for this time range") or one value from the range applies (e.g. "give to the patient between these two times").

Period is not used for a duration (a measure of elapsed time). See Duration.

The description and/or reference of the event(s) being documented. For example, this could be used to document such a colonoscopy or an appendectomy.

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

A code identifying the kind of content contained within the section. This must be consistent with the section title.

Provides computable standardized labels to topics within the document.

The code identifies the section for an automated processor of the document. This is particularly relevant when using profiles to control the structure of the document.

If the section has content (instead of sub-sections), the section.code does not change the meaning or interpretation of the resource that is the content of the section in the comments for the section.code.

Identifies who is responsible for the information in this section, not necessarily who typed it in.