Defines the characteristics of a message that can be shared between systems, including the type of event that initiates the message, the content to be transmitted and what response(s), if any, are permitted.

This would be a MIF-level artifact.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element.

This element is labelled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation.

An Extension

R4: MessageDefinition.graph (new:canonical(GraphDefinition))

Element MessageDefinition.graph has a context of MessageDefinition based on following the parent source element upwards and mapping to MessageDefinition. Element MessageDefinition.graph has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).

May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

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.

The status of this message definition. Enables tracking the life-cycle of the content.

Allows filtering of message definitions that are appropriate for use vs. not.
This is labeled as "Is Modifier" because applications should not use a retired message definition without due consideration.

The lifecycle status of a Value Set or Concept Map.

A boolean value to indicate that this message definition is authored for testing purposes (or education/evaluation/marketing), and is not intended to be used for genuine usage.

Allows filtering of message definition that are appropriate for use vs. not. This is labeled as "Is Modifier" because applications should not use an experimental message definition in production.

Enables experimental content to be developed following the same lifecycle that would be used for a production-level message definition.

The date (and optionally time) when the message definition was published. The date must change if and when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the message definition changes.

Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the message definition. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

A coded identifier of a supported messaging event.

One of the message events defined as part of FHIR.

An Extension

R4: MessageDefinition.event[x] additional types (uri) additional types from child elements (value)

Element MessageDefinition.event[x] is mapped to FHIR STU3 element MessageDefinition.event as SourceIsBroaderThanTarget. The mappings for MessageDefinition.event[x] do not cover the following types: uri. The mappings for MessageDefinition.event[x] do not cover the following types based on type expansion: value.

R4: MessageDefinition.graph (new:canonical(GraphDefinition))

Element MessageDefinition.graph has a context of MessageDefinition based on following the parent source element upwards and mapping to MessageDefinition. Element MessageDefinition.graph has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).

R4: MessageDefinition.base additional types (canonical(http://hl7.org/fhir/StructureDefinition/MessageDefinition)) additional types from child elements (value)

Element MessageDefinition.base is mapped to FHIR STU3 element MessageDefinition.base as SourceIsBroaderThanTarget. The mappings for MessageDefinition.base do not cover the following types: canonical. The mappings for MessageDefinition.base do not cover the following types based on type expansion: value.

R4: MessageDefinition.parent additional types (canonical(http://hl7.org/fhir/StructureDefinition/ActivityDefinition), canonical(http://hl7.org/fhir/StructureDefinition/PlanDefinition)) additional types from child elements (value)

Element MessageDefinition.parent is mapped to FHIR STU3 element MessageDefinition.parent as SourceIsBroaderThanTarget. The mappings for MessageDefinition.parent do not cover the following types: canonical. The mappings for MessageDefinition.parent do not cover the following types based on type expansion: value. It should be possible to use MessageDefinition to describe a message to be used by certain steps in a particular protocol as part of a PlanDefinition or ActivityDefinition.

R4: MessageDefinition.replaces additional types (canonical(http://hl7.org/fhir/StructureDefinition/MessageDefinition)) additional types from child elements (value)

Element MessageDefinition.replaces is mapped to FHIR STU3 element MessageDefinition.replaces as SourceIsBroaderThanTarget. The mappings for MessageDefinition.replaces do not cover the following types: canonical. The mappings for MessageDefinition.replaces do not cover the following types based on type expansion: value.

R4: MessageDefinition.event[x] additional types (uri) additional types from child elements (value)

Element MessageDefinition.event[x] is mapped to FHIR STU3 element MessageDefinition.event as SourceIsBroaderThanTarget. The mappings for MessageDefinition.event[x] do not cover the following types: uri. The mappings for MessageDefinition.event[x] do not cover the following types based on type expansion: value.

R4: MessageDefinition.focus.code

Element MessageDefinition.focus.code is mapped to FHIR STU3 element MessageDefinition.focus.code as SourceIsBroaderThanTarget. Multiple focuses addressing different resources may occasionally occur. E.g. to link or unlink a resource from a particular account or encounter, etc.

R4: MessageDefinition.focus.profile additional types (canonical(http://hl7.org/fhir/StructureDefinition/StructureDefinition)) additional types from child elements (value)

Element MessageDefinition.focus.profile is mapped to FHIR STU3 element MessageDefinition.focus.profile as SourceIsBroaderThanTarget. The mappings for MessageDefinition.focus.profile do not cover the following types: canonical. The mappings for MessageDefinition.focus.profile do not cover the following types based on type expansion: value. This should be present for most message definitions. However, if the message focus is only a single resource and there is no need to include referenced resources or otherwise enforce the presence of particular elements, it can be omitted.

R4: MessageDefinition.responseRequired additional types (code) additional types from child elements (value)

Element MessageDefinition.responseRequired is mapped to FHIR STU3 element MessageDefinition.responseRequired as SourceIsBroaderThanTarget. The mappings for MessageDefinition.responseRequired do not cover the following types: code. The mappings for MessageDefinition.responseRequired do not cover the following types based on type expansion: value. This enables the capability currently available through MSH-16 (Application Level acknowledgement) in HL7 Version 2 to declare at a message instance level whether a response is required or only upon error or success, or never.

R4: MessageDefinition.allowedResponse.message additional types (canonical(http://hl7.org/fhir/StructureDefinition/MessageDefinition)) additional types from child elements (value)

Element MessageDefinition.allowedResponse.message is mapped to FHIR STU3 element MessageDefinition.allowedResponse.message as SourceIsBroaderThanTarget. The mappings for MessageDefinition.allowedResponse.message do not cover the following types: canonical. The mappings for MessageDefinition.allowedResponse.message do not cover the following types based on type expansion: value.

Defines the characteristics of a message that can be shared between systems, including the type of event that initiates the message, the content to be transmitted and what response(s), if any, are permitted.

This would be a MIF-level artifact.

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 may not always be associated with version changes to the resource.

A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content.

Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element.

This element is labelled as a modifier because the implicit rules may provide additional knowledge about the resource that modifies it's meaning or interpretation.

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).

A human language.

A human-readable narrative that contains a summary of the resource, and may be used to represent the content of the resource to a human. The narrative need not encode all the structured data, but is required to contain sufficient detail to make it "clinically safe" for a human to just read the narrative. Resource definitions may define what content should be represented in the narrative to ensure clinical safety.

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.

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.

An Extension

R4: MessageDefinition.graph (new:canonical(GraphDefinition))

Element MessageDefinition.graph has a context of MessageDefinition based on following the parent source element upwards and mapping to MessageDefinition. Element MessageDefinition.graph has no mapping targets in FHIR STU3. Typically, this is because the element has been added (is a new element).

May be used to represent additional information that is not part of the basic definition of the resource, and that modifies the understanding of the element that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

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.

An absolute URI that is used to identify this message definition when it is referenced in a specification, model, design or an instance. This SHALL be a URL, SHOULD be globally unique, and SHOULD be an address at which this message definition is (or will be) published. The URL SHOULD include the major version of the message definition. For more information see Technical and Business Versions.

Can be a urn:uuid: or a urn:oid:, but real http: addresses are preferred. Multiple instances may share the same url if they have a distinct version.

Allows the message definition to be referenced by a single globally unique identifier.

A formal identifier that is used to identify this message definition when it is represented in other formats, or referenced in a specification, model, design or an instance.

Typically, this is used for identifiers that can go in an HL7 V3 II (instance identifier) data type, e.g., to identify this message definition outside of FHIR, where it is not possible to use the logical URI.

Allows externally provided and/or usable business identifiers to be easily associated with the module.

The identifier that is used to identify this version of the message definition when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the message definition author and is not expected to be globally unique. For example, it might be a timestamp (e.g. yyyymmdd) if a managed version is not available. There is also no expectation that versions can be placed in a lexicographical sequence.

There may be different message definition instances that have the same identifier but different versions. The version can be appended to the url in a reference to allow a refrence to a particular business version of the message definition with the format [url]|[version].

A natural language name identifying the message definition. This name should be usable as an identifier for the module by machine processing applications such as code generation.

The name is not expected to be globally unique. The name should be a simple alpha-numeric type name to ensure that it is computable friendly.

Support human navigation and code generation.

A short, descriptive, user-friendly title for the message definition.

This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.

The status of this message definition. Enables tracking the life-cycle of the content.

Allows filtering of message definitions that are appropriate for use vs. not.
This is labeled as "Is Modifier" because applications should not use a retired message definition without due consideration.

The lifecycle status of a Value Set or Concept Map.

A boolean value to indicate that this message definition is authored for testing purposes (or education/evaluation/marketing), and is not intended to be used for genuine usage.

Allows filtering of message definition that are appropriate for use vs. not. This is labeled as "Is Modifier" because applications should not use an experimental message definition in production.

Enables experimental content to be developed following the same lifecycle that would be used for a production-level message definition.

The date (and optionally time) when the message definition was published. The date must change if and when the business version changes and it must change if the status code changes. In addition, it should change when the substantive content of the message definition changes.

Note that this is not the same as the resource last-modified-date, since the resource may be a secondary representation of the message definition. Additional specific dates may be added as extensions or be found by consulting Provenances associated with past versions of the resource.

The name of the individual or organization that published the message definition.

Usually an organization, but may be an individual. The publisher (or steward) of the message definition is the organization or individual primarily responsible for the maintenance and upkeep of the message definition. This is not necessarily the same individual or organization that developed and initially authored the content. The publisher is the primary point of contact for questions or issues with the message definition. This item SHOULD be populated unless the information is available from context.

Helps establish the "authority/credibility" of the message definition. May also allow for contact.

Contact details to assist a user in finding and communicating with the publisher.

May be a web site, an email address, a telephone number, etc.

A free text natural language description of the message definition from a consumer's perspective.

This description can be used to capture details such as why the message definition was built, comments about misuse, instructions for clinical use and interpretation, literature references, examples from the paper world, etc. It is not a rendering of the message definition as conveyed in the 'text' field of the resource itself. This item SHOULD be populated unless the information is available from context (e.g. the language of the profile is presumed to be the predominant language in the place the profile was created).

The content was developed with a focus and intent of supporting the contexts that are listed. These terms may be used to assist with indexing and searching for appropriate message definition instances.

When multiple useContexts are specified, there is no expectation whether all or any of the contexts apply.

Assist in searching for appropriate content.

A legal or geographic region in which the message definition is intended to be used.

It may be possible for the message definition to be used in jurisdictions other than those for which it was originally designed or intended.

Countries and regions within which this artifact is targeted for use

Explaination of why this message definition is needed and why it has been designed as it has.

This element does not describe the usage of the message definition Instead it provides traceability of ''why'' the resource is either needed or ''why'' it is defined as it is. This may be used to point to source materials or specifications that drove the structure of this message definition.

A copyright statement relating to the message definition and/or its contents. Copyright statements are generally legal restrictions on the use and publishing of the message definition.

Consumers must be able to determine any legal restrictions on the use of the message definition and/or its content.

The MessageDefinition that is the basis for the contents of this 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

R4: MessageDefinition.base additional types (canonical(http://hl7.org/fhir/StructureDefinition/MessageDefinition)) additional types from child elements (value)

Element MessageDefinition.base is mapped to FHIR STU3 element MessageDefinition.base as SourceIsBroaderThanTarget. The mappings for MessageDefinition.base do not cover the following types: canonical. The mappings for MessageDefinition.base do not cover the following types based on type expansion: value.

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.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

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.

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.

Identifies a protocol or workflow that this MessageDefinition represents a step in.

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

An Extension

R4: MessageDefinition.parent additional types (canonical(http://hl7.org/fhir/StructureDefinition/ActivityDefinition), canonical(http://hl7.org/fhir/StructureDefinition/PlanDefinition)) additional types from child elements (value)

Element MessageDefinition.parent is mapped to FHIR STU3 element MessageDefinition.parent as SourceIsBroaderThanTarget. The mappings for MessageDefinition.parent do not cover the following types: canonical. The mappings for MessageDefinition.parent do not cover the following types based on type expansion: value. It should be possible to use MessageDefinition to describe a message to be used by certain steps in a particular protocol as part of a PlanDefinition or ActivityDefinition.

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.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

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.

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 MessageDefinition that is superseded by this definition.

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

An Extension

R4: MessageDefinition.replaces additional types (canonical(http://hl7.org/fhir/StructureDefinition/MessageDefinition)) additional types from child elements (value)

Element MessageDefinition.replaces is mapped to FHIR STU3 element MessageDefinition.replaces as SourceIsBroaderThanTarget. The mappings for MessageDefinition.replaces do not cover the following types: canonical. The mappings for MessageDefinition.replaces do not cover the following types based on type expansion: value.

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.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

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.

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 coded identifier of a supported messaging event.

One of the message events defined as part of FHIR.

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

An Extension

R4: MessageDefinition.event[x] additional types (uri) additional types from child elements (value)

Element MessageDefinition.event[x] is mapped to FHIR STU3 element MessageDefinition.event as SourceIsBroaderThanTarget. The mappings for MessageDefinition.event[x] do not cover the following types: uri. The mappings for MessageDefinition.event[x] do not cover the following types based on type expansion: value.

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

The URI may be an OID (urn:oid:...) or a UUID (urn:uuid:...). OIDs and UUIDs SHALL be references to the HL7 OID registry. Otherwise, the URI should come from HL7's list of FHIR defined special URIs or it should de-reference to some definition that establish the system clearly and unambiguously.

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

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 symbol in syntax defined by the system. The symbol may be a predefined code or an expression in a syntax defined by the coding system (e.g. post-coordination).

Need to refer to a particular code in the system.

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.

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

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.

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.

The impact of the content of the message.

The impact of the content of a message.

Identifies the resource (or resources) that are being addressed by the event. For example, the Encounter for an admit message or two Account records for a merge.

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. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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 that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

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.

The kind of resource that must be the focus for this message.

Multiple focuses addressing different resources may occasionally occur. E.g. to link or unlink a resource from a particular account or encounter, etc.

The codes SHALL be taken from ResourceType
(required to http://hl7.org/fhir/ValueSet/resource-types|3.0.2)

One of the resource types defined as part of FHIR.

unique id for the element within a resource (for internal references)

An Extension

R4: MessageDefinition.focus.code

Element MessageDefinition.focus.code is mapped to FHIR STU3 element MessageDefinition.focus.code as SourceIsBroaderThanTarget. Multiple focuses addressing different resources may occasionally occur. E.g. to link or unlink a resource from a particular account or encounter, etc.

Primitive value for code

A profile that reflects constraints for the focal resource (and potentially for related resources).

This should be present for most message definitions. However, if the message focus is only a single resource and there is no need to include referenced resources or otherwise enforce the presence of particular elements, it can be omitted.

This profile allows setting boundaries for what content must appear within the message bundle vs. outside based on the declared aggregation constraints on referenced resources on this and related profiles.

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

An Extension

R4: MessageDefinition.focus.profile additional types (canonical(http://hl7.org/fhir/StructureDefinition/StructureDefinition)) additional types from child elements (value)

Element MessageDefinition.focus.profile is mapped to FHIR STU3 element MessageDefinition.focus.profile as SourceIsBroaderThanTarget. The mappings for MessageDefinition.focus.profile do not cover the following types: canonical. The mappings for MessageDefinition.focus.profile do not cover the following types based on type expansion: value. This should be present for most message definitions. However, if the message focus is only a single resource and there is no need to include referenced resources or otherwise enforce the presence of particular elements, it can be omitted.

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.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

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.

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.

Identifies the minimum number of resources of this type that must be pointed to by a message in order for it to be valid against this MessageDefinition.

Identifies the maximum number of resources of this type that must be pointed to by a message in order for it to be valid against this MessageDefinition.

Indicates whether a response is required for this message.

unique id for the element within a resource (for internal references)

An Extension

R4: MessageDefinition.responseRequired additional types (code) additional types from child elements (value)

Element MessageDefinition.responseRequired is mapped to FHIR STU3 element MessageDefinition.responseRequired as SourceIsBroaderThanTarget. The mappings for MessageDefinition.responseRequired do not cover the following types: code. The mappings for MessageDefinition.responseRequired do not cover the following types based on type expansion: value. This enables the capability currently available through MSH-16 (Application Level acknowledgement) in HL7 Version 2 to declare at a message instance level whether a response is required or only upon error or success, or never.

The actual value

Indicates what types of messages may be sent as an application-level response to this message.

This indicates an application level response to "close" a transaction implicit in a particular request message. To define a complete workflow scenario, look to the [[PlanDefinition]] resource which allows the definition of complex orchestrations, conditionality, etc.

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. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

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 that contains it. Usually modifier elements provide negation or qualification. In order to make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer is allowed to define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension. Applications processing a resource are required to check for modifier extensions.

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.

A reference to the message definition that must be adhered to by this supported response.

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

An Extension

R4: MessageDefinition.allowedResponse.message additional types (canonical(http://hl7.org/fhir/StructureDefinition/MessageDefinition)) additional types from child elements (value)

Element MessageDefinition.allowedResponse.message is mapped to FHIR STU3 element MessageDefinition.allowedResponse.message as SourceIsBroaderThanTarget. The mappings for MessageDefinition.allowedResponse.message do not cover the following types: canonical. The mappings for MessageDefinition.allowedResponse.message do not cover the following types based on type expansion: value.

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.

An identifier for the other resource. This is used when there is no way to reference the other resource directly, either because the entity is not available through a FHIR server, or because there is no way for the author of the resource to convert a known identifier to an actual location. There is no requirement that a Reference.identifier point to something that is actually exposed as a FHIR instance, but it SHALL point to a business concept that would be expected to be exposed as a FHIR instance, and that instance would need to be of a FHIR resource type allowed by the reference.

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.

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.

Provides a description of the circumstances in which this response should be used (as opposed to one of the alternative responses).