Clinical Practice Guidelines
2.0.0-draft - draft International flag

Clinical Practice Guidelines, published by HL7 International / Clinical Decision Support. This guide is not an authorized publication; it is the continuous build for version 2.0.0-draft built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/cqf-recommendations/ and changes regularly. See the Directory of published versions

Resource Profile: CPGCaseFeatureDefinition - Detailed Descriptions

Active as of 2024-06-06

Definitions for the cpg-casefeaturedefinition resource profile.

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

0. StructureDefinition
2. StructureDefinition.extension
SlicingThis element introduces a set of slices on StructureDefinition.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
  • value @ url
  • 4. StructureDefinition.extension:inferenceExpression
    Slice NameinferenceExpression
    Control0..1
    TypeExtension(CPG Inference Expression Extension) (Extension Type: Expression)
    Must Supporttrue
    6. StructureDefinition.extension:assertionExpression
    Slice NameassertionExpression
    Control0..1
    TypeExtension(CPG Assertion Expression Extension) (Extension Type: Expression)
    Must Supporttrue
    8. StructureDefinition.extension:featureExpression
    Slice NamefeatureExpression
    Control0..1
    TypeExtension(CPG Feature Expression Extension) (Extension Type: Expression)
    Must Supporttrue
    10. StructureDefinition.extension:caseFeatureOf
    Slice NamecaseFeatureOf
    Control0..*
    TypeExtension(CPG Case Feature Of Extension) (Extension Type: canonical)
    Must Supporttrue
    12. StructureDefinition.kind
    Fixed Valueresource
    14. StructureDefinition.abstract
    Fixed Valuefalse
    16. StructureDefinition.derivation
    Control1..?
    Fixed Valueconstraint

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

    0. StructureDefinition
    Definition

    A definition of a FHIR structure. This resource is used to describe the underlying resources, data types defined in FHIR, and also for describing extensions and constraints on resources and data types.

    ShortStructural Definition
    Control0..*
    Is Modifierfalse
    Summaryfalse
    Alternate NamesTemplate, Profile
    Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
    dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
    dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
    dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
    dom-6: A resource should have narrative for robust management (text.`div`.exists())
    sdf-0: Name should be usable as an identifier for the module by machine processing applications such as code generation (name.matches('[A-Z]([A-Za-z0-9_]){0,254}'))
    sdf-1: Element paths must be unique unless the structure is a constraint (derivation = 'constraint' or snapshot.element.select(path).isDistinct())
    sdf-15a: If the first element in a differential has no "." in the path and it's not a logical model, it has no type ((kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty())
    sdf-4: If the structure is not abstract, then there SHALL be a baseDefinition (abstract = true or baseDefinition.exists())
    sdf-5: If the structure defines an extension then the structure must have context information (type != 'Extension' or derivation = 'specialization' or (context.exists()))
    sdf-6: A structure must have either a differential, or a snapshot (or both) (snapshot.exists() or differential.exists())
    sdf-9: In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) (children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty())
    sdf-11: If there's a type, its content must match the path name in the first element of a snapshot (kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type)
    sdf-14: All element definitions must have an id (snapshot.element.all(id.exists()) and differential.element.all(id.exists()))
    sdf-15: The first element in a snapshot has no type unless model is a logical model. (kind!='logical' implies snapshot.element.first().type.empty())
    sdf-16: All element definitions must have unique ids (snapshot) (snapshot.element.all(id.exists()) and snapshot.element.id.trace('ids').isDistinct())
    sdf-17: All element definitions must have unique ids (diff) (differential.element.all(id.exists()) and differential.element.id.trace('ids').isDistinct())
    sdf-18: Context Invariants can only be used for extensions (contextInvariant.exists() implies type = 'Extension')
    sdf-19: FHIR Specification models only use FHIR defined types (url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential.element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) and snapshot.element.type.code.all(matches('^[a-zA-Z0-9\\.]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$'))))
    sdf-21: Default values can only be specified on specializations (differential.element.defaultValue.exists() implies (derivation = 'specialization'))
    sdf-22: FHIR Specification models never have default values (url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty()))
    sdf-23: No slice name on root ((snapshot | differential).element.all(path.contains('.').not() implies sliceName.empty()))
    sdf-0: Name should be usable as an identifier for the module by machine processing applications such as code generation (name.matches('[A-Z]([A-Za-z0-9_]){0,254}'))
    sdf-1: Element paths must be unique unless the structure is a constraint (derivation = 'constraint' or snapshot.element.select(path).isDistinct())
    sdf-15a: If the first element in a differential has no "." in the path and it's not a logical model, it has no type ((kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty())
    sdf-4: If the structure is not abstract, then there SHALL be a baseDefinition (abstract = true or baseDefinition.exists())
    sdf-5: If the structure defines an extension then the structure must have context information (type != 'Extension' or derivation = 'specialization' or (context.exists()))
    sdf-6: A structure must have either a differential, or a snapshot (or both) (snapshot.exists() or differential.exists())
    sdf-9: In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) (children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty())
    sdf-11: If there's a type, its content must match the path name in the first element of a snapshot (kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type)
    sdf-14: All element definitions must have an id (snapshot.element.all(id.exists()) and differential.element.all(id.exists()))
    sdf-15: The first element in a snapshot has no type unless model is a logical model. (kind!='logical' implies snapshot.element.first().type.empty())
    sdf-16: All element definitions must have unique ids (snapshot) (snapshot.element.all(id.exists()) and snapshot.element.id.trace('ids').isDistinct())
    sdf-17: All element definitions must have unique ids (diff) (differential.element.all(id.exists()) and differential.element.id.trace('ids').isDistinct())
    sdf-18: Context Invariants can only be used for extensions (contextInvariant.exists() implies type = 'Extension')
    sdf-19: FHIR Specification models only use FHIR defined types (url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential.element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) and snapshot.element.type.code.all(matches('^[a-zA-Z0-9\\.]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$'))))
    sdf-21: Default values can only be specified on specializations (differential.element.defaultValue.exists() implies (derivation = 'specialization'))
    sdf-22: FHIR Specification models never have default values (url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty()))
    sdf-23: No slice name on root ((snapshot | differential).element.all(path.contains('.').not() implies sliceName.empty()))
    2. StructureDefinition.implicitRules
    Definition

    A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

    ShortA set of rules under which this content was created
    Comments

    Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

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

    An Extension


    May be used to represent additional information that is not part of the basic definition of the resource. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

    ShortExtensionAdditional content defined by implementations
    Comments

    There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

      Defines formal computational semantics for calculating the case feature if it is not asserted.

      ShortCPG Inference Expression Extension
      Control0..1
      This element is affected by the following invariants: ele-1
      TypeExtension(CPG Inference Expression Extension) (Extension Type: Expression)
      Is Modifierfalse
      Must Supporttrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      8. StructureDefinition.extension:assertionExpression
      Slice NameassertionExpression
      Definition

      Defines formal computational semantics for the feature if it is asserted. This is typically only required if the case feature is of a different type than the profile (e.g. a boolean feature).

      ShortCPG Assertion Expression Extension
      Control0..1
      This element is affected by the following invariants: ele-1
      TypeExtension(CPG Assertion Expression Extension) (Extension Type: Expression)
      Is Modifierfalse
      Must Supporttrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      10. StructureDefinition.extension:featureExpression
      Slice NamefeatureExpression
      Definition

      Defines formal computational semantics for the feature, combining the inference and assertion expressions. This is typically only required if the feature is of a different type than the profile (e.g. a boolean feature).

      ShortCPG Feature Expression Extension
      Control0..1
      This element is affected by the following invariants: ele-1
      TypeExtension(CPG Feature Expression Extension) (Extension Type: Expression)
      Is Modifierfalse
      Must Supporttrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      12. StructureDefinition.extension:caseFeatureOf
      Slice NamecaseFeatureOf
      Definition

      Defines which guideline elements this case feature definition is a feature of.

      ShortCPG Case Feature Of Extension
      Control0..*
      This element is affected by the following invariants: ele-1
      TypeExtension(CPG Case Feature Of Extension) (Extension Type: canonical)
      Is Modifierfalse
      Must Supporttrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
      14. StructureDefinition.modifierExtension
      Definition

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

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

      ShortExtensions that cannot be ignored
      Comments

      There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

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

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

      An absolute URI that is used to identify this structure definition when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which at which an authoritative instance of this structure definition is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the structure definition is stored on different servers.

      ShortCanonical identifier for this structure definition, represented as a URI (globally unique)
      Comments

      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.

      The determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author. Considerations for making this decision are found in Technical and Business Versions.

      In some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the meta.source element to indicate where the current master source of the resource can be found.

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

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

      Alternate Namesurl, authoritative-url, destination, identity
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      18. StructureDefinition.name
      Definition

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

      ShortName for this structure definition (computer friendly)
      Comments

      The name is not expected to be globally unique. The name should be a simple alphanumeric type name to ensure that it is machine-processing friendly.Some Examples:

      • O2SatObservation
      • PresentationReport
      • Immunization2
      • AcmeAdmissionRecordOld.
      Control1..1
      This element is affected by the following invariants: inv-0
      Typestring
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Requirements

      Support human navigation and code generation.

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

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

      Shortdraft | active | retired | unknown
      Comments

      Allows filtering of structure definitions that are appropriate for use versus not.

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

      The lifecycle status of an artifact.

      Typecode
      Is Modifiertrue because This is labeled as "Is Modifier" because applications should not use a retired {{title}} without due consideration
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      22. StructureDefinition.kind
      Definition

      Defines the kind of structure that this definition is describing.

      Shortprimitive-type | complex-type | resource | logical
      Control1..1
      BindingThe codes SHALL be taken from StructureDefinitionKindhttp://hl7.org/fhir/ValueSet/structure-definition-kind|4.0.1
      (required to http://hl7.org/fhir/ValueSet/structure-definition-kind|4.0.1)

      Defines the type of structure that a definition is describing.

      Typecode
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Fixed Valueresource
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      24. StructureDefinition.abstract
      Definition

      Whether structure this definition describes is abstract or not - that is, whether the structure is not intended to be instantiated. For Resources and Data types, abstract types will never be exchanged between systems.

      ShortWhether the structure is abstract
      Comments

      Abstract Resources cannot be instantiated - a concrete sub-type must be used. Abstract datatypes and extensions cannot be used in an instance. For logical models, the exact implication of "abstract" will rest with the author, depending how the logical model is used. Flagging a constraint structure as abstract conveys design intent but makes no difference to how the structure definition is handled. Note that inline declared elements that are given the type "Element" in the StructureDefinition, but have children described, are anonymous concrete types that specialize Element.

      Control1..1
      Typeboolean
      Is Modifierfalse
      Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
      Summarytrue
      Fixed Valuefalse
      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      26. StructureDefinition.type
      Definition

      The type this structure describes. If the derivation kind is 'specialization' then this is the master definition for a type, and there is always one of these (a data type, an extension, a resource, including abstract ones). Otherwise the structure definition is a constraint on the stated type (and in this case, the type cannot be an abstract type). References are URLs that are relative to http://hl7.org/fhir/StructureDefinition e.g. "string" is a reference to http://hl7.org/fhir/StructureDefinition/string. Absolute URLs are only allowed in logical models.

      ShortType defined or constrained by this structure
      Comments

      Note that in the case of constraints, the type could be determined by chasing through the baseDefinition references until a concrete structure (derivation = specialization) is reached, or by looking at the path of the first element in the snapshot - if present - but providing the type directly makes for simpler tooling and indexing.

      The type must match the elements defined in the differential and the snapshot. For all FHIR defined types, the path name of the element will start with the type name. For logical models, where the type is a URL, the type name SHOULD start with the tail of the type URL where required.

      Control1..1
      This element is affected by the following invariants: sdf-11
      BindingUnless not suitable, these codes SHALL be taken from FHIRDefinedTypehttp://hl7.org/fhir/ValueSet/defined-types
      (extensible to http://hl7.org/fhir/ValueSet/defined-types)

      Either a resource or a data type, including logical model types.

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

      How the type relates to the baseDefinition.

      Shortspecialization | constraint - How relates to base definition
      Comments

      If the definition is a specialization, then it adds new elements in the differential, and the snapshot includes the inherited elements. If the definition is a constraint, then it cannot define new elements, it can only make new rules about existing content (see Profiling Resources).

      Control10..1
      BindingThe codes SHALL be taken from TypeDerivationRulehttp://hl7.org/fhir/ValueSet/type-derivation-rule|4.0.1
      (required to http://hl7.org/fhir/ValueSet/type-derivation-rule|4.0.1)

      How a type relates to its baseDefinition.

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

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

      0. StructureDefinition
      Definition

      A definition of a FHIR structure. This resource is used to describe the underlying resources, data types defined in FHIR, and also for describing extensions and constraints on resources and data types.

      ShortStructural Definition
      Control0..*
      Is Modifierfalse
      Summaryfalse
      Alternate NamesTemplate, Profile
      Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.empty())
      dom-3: If the resource is contained in another resource, it SHALL be referred to from elsewhere in the resource or SHALL refer to the containing resource (contained.where((('#'+id in (%resource.descendants().reference | %resource.descendants().as(canonical) | %resource.descendants().as(uri) | %resource.descendants().as(url))) or descendants().where(reference = '#').exists() or descendants().where(as(canonical) = '#').exists() or descendants().where(as(canonical) = '#').exists()).not()).trace('unmatched', id).empty())
      dom-4: If a resource is contained in another resource, it SHALL NOT have a meta.versionId or a meta.lastUpdated (contained.meta.versionId.empty() and contained.meta.lastUpdated.empty())
      dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
      dom-6: A resource should have narrative for robust management (text.`div`.exists())
      sdf-0: Name should be usable as an identifier for the module by machine processing applications such as code generation (name.matches('[A-Z]([A-Za-z0-9_]){0,254}'))
      sdf-1: Element paths must be unique unless the structure is a constraint (derivation = 'constraint' or snapshot.element.select(path).isDistinct())
      sdf-15a: If the first element in a differential has no "." in the path and it's not a logical model, it has no type ((kind!='logical' and differential.element.first().path.contains('.').not()) implies differential.element.first().type.empty())
      sdf-4: If the structure is not abstract, then there SHALL be a baseDefinition (abstract = true or baseDefinition.exists())
      sdf-5: If the structure defines an extension then the structure must have context information (type != 'Extension' or derivation = 'specialization' or (context.exists()))
      sdf-6: A structure must have either a differential, or a snapshot (or both) (snapshot.exists() or differential.exists())
      sdf-9: In any snapshot or differential, no label, code or requirements on an element without a "." in the path (e.g. the first element) (children().element.where(path.contains('.').not()).label.empty() and children().element.where(path.contains('.').not()).code.empty() and children().element.where(path.contains('.').not()).requirements.empty())
      sdf-11: If there's a type, its content must match the path name in the first element of a snapshot (kind != 'logical' implies snapshot.empty() or snapshot.element.first().path = type)
      sdf-14: All element definitions must have an id (snapshot.element.all(id.exists()) and differential.element.all(id.exists()))
      sdf-15: The first element in a snapshot has no type unless model is a logical model. (kind!='logical' implies snapshot.element.first().type.empty())
      sdf-16: All element definitions must have unique ids (snapshot) (snapshot.element.all(id.exists()) and snapshot.element.id.trace('ids').isDistinct())
      sdf-17: All element definitions must have unique ids (diff) (differential.element.all(id.exists()) and differential.element.id.trace('ids').isDistinct())
      sdf-18: Context Invariants can only be used for extensions (contextInvariant.exists() implies type = 'Extension')
      sdf-19: FHIR Specification models only use FHIR defined types (url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (differential.element.type.code.all(matches('^[a-zA-Z0-9]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$')) and snapshot.element.type.code.all(matches('^[a-zA-Z0-9\\.]+$') or matches('^http:\\/\\/hl7\\.org\\/fhirpath\\/System\\.[A-Z][A-Za-z]+$'))))
      sdf-21: Default values can only be specified on specializations (differential.element.defaultValue.exists() implies (derivation = 'specialization'))
      sdf-22: FHIR Specification models never have default values (url.startsWith('http://hl7.org/fhir/StructureDefinition') implies (snapshot.element.defaultValue.empty() and differential.element.defaultValue.empty()))
      sdf-23: No slice name on root ((snapshot | differential).element.all(path.contains('.').not() implies sliceName.empty()))
      2. StructureDefinition.id
      Definition

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

      ShortLogical id of this artifact
      Comments

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

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

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

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

      A reference to a set of rules that were followed when the resource was constructed, and which must be understood when processing the content. Often, this is a reference to an implementation guide that defines the special rules along with other profiles etc.

      ShortA set of rules under which this content was created
      Comments

      Asserting this rule set restricts the content to be only understood by a limited set of trading partners. This inherently limits the usefulness of the data in the long term. However, the existing health eco-system is highly fractured, and not yet ready to define, collect, and exchange data in a generally computable sense. Wherever possible, implementers and/or specification writers should avoid using this element. Often, when used, the URL is a reference to an implementation guide that defines these special rules as part of it's narrative along with other profiles, value sets, etc.

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

      The base language in which the resource is written.

      ShortLanguage of the resource content
      Comments

      Language is provided to support indexing and accessibility (typically, services such as text to speech use the language tag). The html language tag in the narrative applies to the narrative. The language tag on the resource may be used to specify the language of other presentations generated from the data in the resource. Not all the content has to be in the base language. The Resource.language should not be assumed to apply to the narrative automatically. If a language is specified, it should it also be specified on the div element in the html (see rules in HTML5 for information about the relationship between xml:lang and the html lang attribute).

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

      A human language.

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

      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.

      ShortText summary of the resource, for human interpretation
      Comments

      Contained resources do not have narrative. Resources that are not contained SHOULD have a narrative. In some cases, a resource may only have text with little or no additional discrete data (as long as all minOccurs=1 elements are satisfied). This may be necessary for data from legacy systems where information is captured as a "text blob" or where text is additionally entered raw or narrated and encoded information is added later.

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

      These resources do not have an independent existence apart from the resource that contains them - they cannot be identified independently, and nor can they have their own independent transaction scope.

      ShortContained, inline Resources
      Comments

      This should never be done when the content can be identified properly, as once identification is lost, it is extremely difficult (and context dependent) to restore it again. Contained resources may have profiles and tags In their meta elements, but SHALL NOT have security labels.

      Control0..*
      TypeResource
      Is Modifierfalse
      Summaryfalse
      Alternate Namesinline resources, anonymous resources, contained resources
      14. StructureDefinition.extension
      Definition

      An Extension

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

        Defines formal computational semantics for calculating the case feature if it is not asserted.

        ShortCPG Inference Expression Extension
        Control0..1
        This element is affected by the following invariants: ele-1
        TypeExtension(CPG Inference Expression Extension) (Extension Type: Expression)
        Is Modifierfalse
        Must Supporttrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        18. StructureDefinition.extension:assertionExpression
        Slice NameassertionExpression
        Definition

        Defines formal computational semantics for the feature if it is asserted. This is typically only required if the case feature is of a different type than the profile (e.g. a boolean feature).

        ShortCPG Assertion Expression Extension
        Control0..1
        This element is affected by the following invariants: ele-1
        TypeExtension(CPG Assertion Expression Extension) (Extension Type: Expression)
        Is Modifierfalse
        Must Supporttrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        20. StructureDefinition.extension:featureExpression
        Slice NamefeatureExpression
        Definition

        Defines formal computational semantics for the feature, combining the inference and assertion expressions. This is typically only required if the feature is of a different type than the profile (e.g. a boolean feature).

        ShortCPG Feature Expression Extension
        Control0..1
        This element is affected by the following invariants: ele-1
        TypeExtension(CPG Feature Expression Extension) (Extension Type: Expression)
        Is Modifierfalse
        Must Supporttrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        22. StructureDefinition.extension:caseFeatureOf
        Slice NamecaseFeatureOf
        Definition

        Defines which guideline elements this case feature definition is a feature of.

        ShortCPG Case Feature Of Extension
        Control0..*
        This element is affected by the following invariants: ele-1
        TypeExtension(CPG Case Feature Of Extension) (Extension Type: canonical)
        Is Modifierfalse
        Must Supporttrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        24. StructureDefinition.modifierExtension
        Definition

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

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

        ShortExtensions that cannot be ignored
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

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

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

        An absolute URI that is used to identify this structure definition when it is referenced in a specification, model, design or an instance; also called its canonical identifier. This SHOULD be globally unique and SHOULD be a literal address at which at which an authoritative instance of this structure definition is (or will be) published. This URL can be the target of a canonical reference. It SHALL remain the same when the structure definition is stored on different servers.

        ShortCanonical identifier for this structure definition, represented as a URI (globally unique)
        Comments

        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.

        The determination of when to create a new version of a resource (same url, new version) vs. defining a new artifact is up to the author. Considerations for making this decision are found in Technical and Business Versions.

        In some cases, the resource can no longer be found at the stated url, but the url itself cannot change. Implementations can use the meta.source element to indicate where the current master source of the resource can be found.

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

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

        Alternate Namesurl, authoritative-url, destination, identity
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        28. StructureDefinition.identifier
        Definition

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

        ShortAdditional identifier for the structure definition
        Comments

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

        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control0..*
        TypeIdentifier
        Is Modifierfalse
        Summarytrue
        Requirements

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

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

        The identifier that is used to identify this version of the structure definition when it is referenced in a specification, model, design or instance. This is an arbitrary value managed by the structure 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.

        ShortBusiness version of the structure definition
        Comments

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

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

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

        ShortName for this structure definition (computer friendly)
        Comments

        The name is not expected to be globally unique. The name should be a simple alphanumeric type name to ensure that it is machine-processing friendly.Some Examples:

        • O2SatObservation
        • PresentationReport
        • Immunization2
        • AcmeAdmissionRecordOld.
        Control1..1
        This element is affected by the following invariants: inv-0
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Requirements

        Support human navigation and code generation.

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

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

        ShortName for this structure definition (human friendly)
        Comments

        This name does not need to be machine-processing friendly and may contain punctuation, white-space, etc.Applications don't have to use this name but can always fall back to it. The title also corresponds to the label for the root element.

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

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

        Shortdraft | active | retired | unknown
        Comments

        Allows filtering of structure definitions that are appropriate for use versus not.

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

        The lifecycle status of an artifact.

        Typecode
        Is Modifiertrue because This is labeled as "Is Modifier" because applications should not use a retired {{title}} without due consideration
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        38. StructureDefinition.experimental
        Definition

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

        ShortFor testing purposes, not real usage
        Comments

        Allows filtering of structure definitions that are appropriate for use versus not.

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

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

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

        The date (and optionally time) when the structure definition was published. The date must change 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 structure definition changes.

        ShortDate last changed
        Comments

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

        Control0..1
        TypedateTime
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Alternate NamesRevision Date
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        42. StructureDefinition.publisher
        Definition

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

        ShortName of the publisher (organization or individual)
        Comments

        Usually an organization but may be an individual. The publisher (or steward) of the structure definition is the organization or individual primarily responsible for the maintenance and upkeep of the structure 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 structure definition. This item SHOULD be populated unless the information is available from context.

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

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

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

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

        ShortContact details for the publisher
        Comments

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

        Control0..*
        TypeContactDetail
        Is Modifierfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        46. StructureDefinition.description
        Definition

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

        ShortNatural language description of the structure definition
        Comments

        This description can be used to capture details such as why the structure 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 structure 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 structure definition is presumed to be the predominant language in the place the structure definition was created).

        Control0..1
        Typemarkdown
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        48. StructureDefinition.useContext
        Definition

        The content was developed with a focus and intent of supporting the contexts that are listed. These contexts may be general categories (gender, age, ...) or may be references to specific programs (insurance plans, studies, ...) and may be used to assist with indexing and searching for appropriate structure definition instances.

        ShortThe context that the content is intended to support
        Comments

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

        Control0..*
        TypeUsageContext
        Is Modifierfalse
        Summarytrue
        Requirements

        Assist in searching for appropriate content.

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

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

        ShortIntended jurisdiction for structure definition (if applicable)
        Comments

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

        Control0..*
        BindingUnless not suitable, these codes SHALL be taken from Jurisdiction ValueSet
        (extensible to http://hl7.org/fhir/ValueSet/jurisdiction)

        Countries and regions within which this artifact is targeted for use.

        TypeCodeableConcept
        Is Modifierfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        52. StructureDefinition.purpose
        Definition

        Explanation of why this structure definition is needed and why it has been designed as it has.

        ShortWhy this structure definition is defined
        Comments

        This element does not describe the usage of the structure 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 structure definition.

        Control0..1
        Typemarkdown
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        54. StructureDefinition.copyright
        Definition

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

        ShortUse and/or publishing restrictions
        Control0..1
        Typemarkdown
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Requirements

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

        Alternate NamesLicense, Restrictions
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        56. StructureDefinition.keyword
        Definition

        A set of key words or terms from external terminologies that may be used to assist with indexing and searching of templates nby describing the use of this structure definition, or the content it describes.

        ShortAssist with indexing and finding
        Control0..*
        BindingUnless not suitable, these codes SHALL be taken from DefinitionUseCodes
        (extensible to http://hl7.org/fhir/ValueSet/definition-use)

        Codes for the meaning of the defined structure (SNOMED CT and LOINC codes, as an example).

        TypeCoding
        Is Modifierfalse
        Summarytrue
        Requirements

        Assist in searching for appropriate StructureDefinitions.

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

        The version of the FHIR specification on which this StructureDefinition is based - this is the formal version of the specification, without the revision number, e.g. [publication].[major].[minor], which is 4.0.1. for this version.

        ShortFHIR Version this StructureDefinition targets
        Comments

        A StructureDefinition does not need to specify the target it applies to as StructureDefinitions will often be valid across multiple versions of FHIR. FHIR tooling can determine whether a StructureDefinition is consistent with a particular StructureDefinition if desired.

        Control0..1
        BindingThe codes SHALL be taken from FHIRVersion
        (required to http://hl7.org/fhir/ValueSet/FHIR-version|4.0.1)

        All published FHIR Versions.

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

        An external specification that the content is mapped to.

        ShortExternal specification that the content is mapped to
        Control0..*
        TypeBackboneElement
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        sdf-2: Must have at least a name or a uri (or both) (name.exists() or uri.exists())
        62. StructureDefinition.mapping.id
        Definition

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

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

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        66. StructureDefinition.mapping.modifierExtension
        Definition

        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).

        ShortExtensions that cannot be ignored even if unrecognized
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

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

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

        An Internal id that is used to identify this mapping set when specific mappings are made.

        ShortInternal id when this mapping is used
        Comments

        The specification is described once, with general comments, and then specific mappings are made that reference this declaration.

        Control1..1
        Typeid
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        70. StructureDefinition.mapping.uri
        Definition

        An absolute URI that identifies the specification that this mapping is expressed to.

        ShortIdentifies what this mapping refers to
        Comments

        A formal identity for the specification being mapped to helps with identifying maps consistently.

        Control0..1
        This element is affected by the following invariants: sdf-2
        Typeuri
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        72. StructureDefinition.mapping.name
        Definition

        A name for the specification that is being mapped to.

        ShortNames what this mapping refers to
        Control0..1
        This element is affected by the following invariants: sdf-2
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        74. StructureDefinition.mapping.comment
        Definition

        Comments about this mapping, including version notes, issues, scope limitations, and other important notes for usage.

        ShortVersions, Issues, Scope limitations etc.
        Control0..1
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        76. StructureDefinition.kind
        Definition

        Defines the kind of structure that this definition is describing.

        Shortprimitive-type | complex-type | resource | logical
        Control1..1
        BindingThe codes SHALL be taken from StructureDefinitionKind
        (required to http://hl7.org/fhir/ValueSet/structure-definition-kind|4.0.1)

        Defines the type of structure that a definition is describing.

        Typecode
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Fixed Valueresource
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        78. StructureDefinition.abstract
        Definition

        Whether structure this definition describes is abstract or not - that is, whether the structure is not intended to be instantiated. For Resources and Data types, abstract types will never be exchanged between systems.

        ShortWhether the structure is abstract
        Comments

        Abstract Resources cannot be instantiated - a concrete sub-type must be used. Abstract datatypes and extensions cannot be used in an instance. For logical models, the exact implication of "abstract" will rest with the author, depending how the logical model is used. Flagging a constraint structure as abstract conveys design intent but makes no difference to how the structure definition is handled. Note that inline declared elements that are given the type "Element" in the StructureDefinition, but have children described, are anonymous concrete types that specialize Element.

        Control1..1
        Typeboolean
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Fixed Valuefalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        80. StructureDefinition.context
        Definition

        Identifies the types of resource or data type elements to which the extension can be applied.

        ShortIf an extension, where it can be used in instances
        Control0..*
        This element is affected by the following invariants: sdf-5
        TypeBackboneElement
        Is Modifierfalse
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        82. StructureDefinition.context.id
        Definition

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

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

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        86. StructureDefinition.context.modifierExtension
        Definition

        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).

        ShortExtensions that cannot be ignored even if unrecognized
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

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

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

        Defines how to interpret the expression that defines what the context of the extension is.

        Shortfhirpath | element | extension
        Control1..1
        BindingThe codes SHALL be taken from ExtensionContextType
        (required to http://hl7.org/fhir/ValueSet/extension-context-type|4.0.1)

        How an extension context is interpreted.

        Typecode
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        90. StructureDefinition.context.expression
        Definition

        An expression that defines where an extension can be used in resources.

        ShortWhere the extension can be used in instances
        Control1..1
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        92. StructureDefinition.contextInvariant
        Definition

        A set of rules as FHIRPath Invariants about when the extension can be used (e.g. co-occurrence variants for the extension). All the rules must be true.

        ShortFHIRPath invariants - when the extension can be used
        Comments

        The rules are only evaluated when the extension is present. When evaluating the invariant, the FHIRPath focus is the element that holds the extension, and %extension refers to the extension itself.

        Control0..*
        This element is affected by the following invariants: sdf-18
        Typestring
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        94. StructureDefinition.type
        Definition

        The type this structure describes. If the derivation kind is 'specialization' then this is the master definition for a type, and there is always one of these (a data type, an extension, a resource, including abstract ones). Otherwise the structure definition is a constraint on the stated type (and in this case, the type cannot be an abstract type). References are URLs that are relative to http://hl7.org/fhir/StructureDefinition e.g. "string" is a reference to http://hl7.org/fhir/StructureDefinition/string. Absolute URLs are only allowed in logical models.

        ShortType defined or constrained by this structure
        Comments

        Note that in the case of constraints, the type could be determined by chasing through the baseDefinition references until a concrete structure (derivation = specialization) is reached, or by looking at the path of the first element in the snapshot - if present - but providing the type directly makes for simpler tooling and indexing.

        The type must match the elements defined in the differential and the snapshot. For all FHIR defined types, the path name of the element will start with the type name. For logical models, where the type is a URL, the type name SHOULD start with the tail of the type URL where required.

        Control1..1
        This element is affected by the following invariants: sdf-11
        BindingUnless not suitable, these codes SHALL be taken from FHIRDefinedType
        (extensible to http://hl7.org/fhir/ValueSet/defined-types)

        Either a resource or a data type, including logical model types.

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

        An absolute URI that is the base structure from which this type is derived, either by specialization or constraint.

        ShortDefinition that this type is constrained/specialized from
        Comments

        If differential constraints are specified in this structure, they are applied to the base in a "differential" fashion. If there is no base, then the differential constraints cannot be provided (snapshot only). Differential structures are useful for the editing perspective, and snapshot structures are suitable for operational use. The FHIR Project provides a number of tools/services to populate snapshots from differential constraints. Logical Models have a base of "Element" or another logical model.

        Control0..1
        This element is affected by the following invariants: sdf-4
        Typecanonical(StructureDefinition)
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        98. StructureDefinition.derivation
        Definition

        How the type relates to the baseDefinition.

        Shortspecialization | constraint - How relates to base definition
        Comments

        If the definition is a specialization, then it adds new elements in the differential, and the snapshot includes the inherited elements. If the definition is a constraint, then it cannot define new elements, it can only make new rules about existing content (see Profiling Resources).

        Control1..1
        BindingThe codes SHALL be taken from TypeDerivationRule
        (required to http://hl7.org/fhir/ValueSet/type-derivation-rule|4.0.1)

        How a type relates to its baseDefinition.

        Typecode
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Summarytrue
        Fixed Valueconstraint
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        100. StructureDefinition.snapshot
        Definition

        A snapshot view is expressed in a standalone form that can be used and interpreted without considering the base StructureDefinition.

        ShortSnapshot view of the structure
        Control0..1
        This element is affected by the following invariants: sdf-6
        TypeBackboneElement
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        sdf-3: Each element definition in a snapshot must have a formal definition and cardinalities (element.all(definition.exists() and min.exists() and max.exists()))
        sdf-8: All snapshot elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models ((%resource.kind = 'logical' or element.first().path = %resource.type) and element.tail().all(path.startsWith(%resource.snapshot.element.first().path&'.')))
        sdf-8b: All snapshot elements must have a base definition (element.all(base.exists()))
        102. StructureDefinition.snapshot.id
        Definition

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

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

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        106. StructureDefinition.snapshot.modifierExtension
        Definition

        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).

        ShortExtensions that cannot be ignored even if unrecognized
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

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

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

        Captures constraints on each element within the resource.

        ShortDefinition of elements in the resource (if no StructureDefinition)
        Control1..*
        This element is affected by the following invariants: sdf-3
        TypeElementDefinition
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        sdf-10: provide either a binding reference or a description (or both) (binding.empty() or binding.valueSet.exists() or binding.description.exists())
        110. StructureDefinition.differential
        Definition

        A differential view is expressed relative to the base StructureDefinition - a statement of differences that it applies.

        ShortDifferential view of the structure
        Control0..1
        This element is affected by the following invariants: sdf-6
        TypeBackboneElement
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        sdf-20: No slicing on the root element (element.where(path.contains('.').not()).slicing.empty())
        sdf-8a: In any differential, all the elements must start with the StructureDefinition's specified type for non-logical models, or with the same type name for logical models ((%resource.kind = 'logical' or element.first().path.startsWith(%resource.type)) and (element.tail().empty() or element.tail().all(path.startsWith(%resource.differential.element.first().path.replaceMatches('\\..*','')&'.'))))
        112. StructureDefinition.differential.id
        Definition

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

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

        May be used to represent additional information that is not part of the basic definition of the element. To make the use of extensions safe and manageable, there is a strict set of governance applied to the definition and use of extensions. Though any implementer can define an extension, there is a set of requirements that SHALL be met as part of the definition of the extension.

        ShortAdditional content defined by implementations
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

        Control0..*
        TypeExtension
        Is Modifierfalse
        Summaryfalse
        Alternate Namesextensions, user content
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        116. StructureDefinition.differential.modifierExtension
        Definition

        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).

        ShortExtensions that cannot be ignored even if unrecognized
        Comments

        There can be no stigma associated with the use of extensions by any application, project, or standard - regardless of the institution or jurisdiction that uses or defines the extensions. The use of extensions is what allows the FHIR specification to retain a core level of simplicity for everyone.

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

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

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

        Captures constraints on each element within the resource.

        ShortDefinition of elements in the resource (if no StructureDefinition)
        Control1..*
        TypeElementDefinition
        Is Modifierfalse
        Summaryfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))