Virtually Healthcare HL7 FHIR Implementation Guide
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Virtually Healthcare HL7 FHIR Implementation Guide, published by Virtually Healthcare. This guide is not an authorized publication; it is the continuous build for version 0.1.0-current built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/Virtually-Healthcare/Virtually-Healthcare-FHIR-Implementation-Guide/ and changes regularly. See the Directory of published versions

Resource Profile: AllergyIntolerance - Detailed Descriptions

Draft as of 2024-11-06

Definitions for the AllergyIntolerance resource profile.

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

0. AllergyIntolerance
2. AllergyIntolerance.identifier
NoteThis is a business identifier, not a resource identifier (see discussion)
Control1..?
Must Supporttrue
SlicingThis element introduces a set of slices on AllergyIntolerance.identifier. The slices areUnordered and Closed, and can be differentiated using the following discriminators:
  • pattern @ system
  • 4. AllergyIntolerance.identifier:CommonResourceIdentifiers
    Slice NameCommonResourceIdentifiers
    ShortCommon Resource Identifiers
    NoteThis is a business identifier, not a resource identifier (see discussion)
    Control0..*
    TypeIdentifier(Common Resource Identifiers)
    6. AllergyIntolerance.patient
    TypeReference(Patient)
    8. AllergyIntolerance.patient.identifier
    NoteThis is a business identifier, not a resource identifier (see discussion)
    TypeIdentifier(NHS, HCSN and CHI Numbers)

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

    0. AllergyIntolerance
    Definition

    Risk of harmful or undesirable, physiological response which is unique to an individual and associated with exposure to a substance.

    ShortAllergy or Intolerance (generally: Risk of adverse reaction to a substance)
    Comments

    Substances include, but are not limited to: a therapeutic substance administered correctly at an appropriate dosage for the individual; food; material derived from plants or animals; or venom from insect stings.

    Control0..*
    Is Modifierfalse
    Alternate NamesAllergy, Intolerance, Adverse Reaction
    Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.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-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-6: A resource should have narrative for robust management (text.`div`.exists())
    dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
    ait-1: AllergyIntolerance.clinicalStatus SHALL be present if verificationStatus is not entered-in-error. (verificationStatus.coding.where(system = 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification' and code = 'entered-in-error').exists() or clinicalStatus.exists())
    ait-2: AllergyIntolerance.clinicalStatus SHALL NOT be present if verification Status is entered-in-error (verificationStatus.coding.where(system = 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification' and code = 'entered-in-error').empty() or clinicalStatus.empty())
    ait-1: AllergyIntolerance.clinicalStatus SHALL be present if verificationStatus is not entered-in-error. (verificationStatus.coding.where(system = 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification' and code = 'entered-in-error').exists() or clinicalStatus.exists())
    ait-2: AllergyIntolerance.clinicalStatus SHALL NOT be present if verification Status is entered-in-error (verificationStatus.coding.where(system = 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification' and code = 'entered-in-error').empty() or clinicalStatus.empty())
    2. AllergyIntolerance.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
    This element is affected by the following invariants: ele-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. AllergyIntolerance.extension:evidence
    Slice Nameevidence
    Definition

    A reference to results of investigations that confirmed the certainty of the diagnosis.

    ShortA reference to results of investigations that confirmed the certainty of the diagnosis.
    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..*
    This element is affected by the following invariants: ele-1
    TypeExtension(Extension UK Core Evidence) (Extension Type: Reference(DiagnosticReport))
    Standard StatusNormative (from Trial Use)
    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())
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    6. AllergyIntolerance.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..*
    This element is affected by the following invariants: ele-1
    TypeExtension
    Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
    Standard StatusNormative (from Trial Use)
    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())
    ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
    SlicingThis element introduces a set of slices on AllergyIntolerance.modifierExtension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
    • value @ url
    • 8. AllergyIntolerance.identifier
      Definition

      Business identifiers assigned to this AllergyIntolerance by the performer or other systems which remain constant as the resource is updated and propagates from server to server.

      ShortExternal ids for this item
      Comments

      This is a business identifier, not a resource identifier (see discussion). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types. For example, multiple Patient and a Person resource instance might share the same social insurance number.

      NoteThis is a business identifier, not a resource identifier (see discussion)
      Control10..*
      This element is affected by the following invariants: ele-1
      TypeIdentifier
      Is Modifierfalse
      Must Supporttrue
      Summarytrue
      Requirements

      Allows identification of the AllergyIntolerance as it is known by various participating systems and in a way that remains consistent across servers.

      Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
      SlicingThis element introduces a set of slices on AllergyIntolerance.identifier. The slices areUnordered and Closed, and can be differentiated using the following discriminators:
      • pattern @ system
      • 10. AllergyIntolerance.identifier:CommonResourceIdentifiers
        Slice NameCommonResourceIdentifiers
        Definition

        An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.


        Business identifiers assigned to this AllergyIntolerance by the performer or other systems which remain constant as the resource is updated and propagates from server to server.

        ShortCommon Resource IdentifiersExternal ids for this item
        Comments

        This is a business identifier, not a resource identifier (see discussion). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types. For example, multiple Patient and a Person resource instance might share the same social insurance number.

        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control0..*
        This element is affected by the following invariants: ele-1
        TypeIdentifier(Common Resource Identifiers)
        Is Modifierfalse
        Requirements

        Allows identification of the AllergyIntolerance as it is known by various participating systems and in a way that remains consistent across servers.

        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        12. AllergyIntolerance.clinicalStatus
        Definition

        The clinical status of the allergy or intolerance.

        Shortactive | inactive | resolved
        Comments

        Refer to discussion if clincalStatus is missing data. The data type is CodeableConcept because clinicalStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.

        Control0..1
        This element is affected by the following invariants: ele-1, ait-1, ait-2
        BindingThe codes SHALL be taken from AllergyIntoleranceClinicalStatusCodeshttp://hl7.org/fhir/ValueSet/allergyintolerance-clinical|4.0.1
        (required to http://hl7.org/fhir/ValueSet/allergyintolerance-clinical|4.0.1)

        The clinical status of the allergy or intolerance.

        TypeCodeableConcept
        Is Modifiertrue because This element is labeled as a modifier because the status contains the codes inactive and resolved that mark the AllergyIntolerance as no longer active.
        Must Supporttrue
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        14. AllergyIntolerance.clinicalStatus.extension:allergyIntoleranceEnd
        Slice NameallergyIntoleranceEnd
        Definition

        Supports the date when the allergy or intolerance was no longer valid, and/or, the reason why the allergy or intolerance is no longer valid.

        ShortSupports the date when the allergy or intolerance was no longer valid, and/or, the reason why the allergy or intolerance is no longer valid.
        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..1
        This element is affected by the following invariants: ele-1
        TypeExtension(Extension UK Core Allergy Intolerance End) (Complex Extension)
        Is Modifierfalse
        Standard StatusNormative (from Trial Use)
        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. AllergyIntolerance.verificationStatus
        Definition

        Assertion about certainty associated with the propensity, or potential risk, of a reaction to the identified substance (including pharmaceutical product).

        Shortunconfirmed | confirmed | refuted | entered-in-error
        Comments

        The data type is CodeableConcept because verificationStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.

        Control0..1
        This element is affected by the following invariants: ele-1, ait-1, ait-2
        BindingThe codes SHALL be taken from AllergyIntoleranceVerificationStatusCodeshttp://hl7.org/fhir/ValueSet/allergyintolerance-verification|4.0.1
        (required to http://hl7.org/fhir/ValueSet/allergyintolerance-verification|4.0.1)

        Assertion about certainty associated with a propensity, or potential risk, of a reaction to the identified substance.

        TypeCodeableConcept
        Is Modifiertrue because This element is labeled as a modifier because the status contains the codes refuted and entered-in-error that mark the AllergyIntolerance as not currently valid.
        Must Supporttrue
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        18. AllergyIntolerance.code
        Definition

        Code for an allergy or intolerance statement (either a positive or a negated/excluded statement). This may be a code for a substance or pharmaceutical product that is considered to be responsible for the adverse reaction risk (e.g., "Latex"), an allergy or intolerance condition (e.g., "Latex allergy"), or a negated/excluded code for a specific substance or class (e.g., "No latex allergy") or a general or categorical negated statement (e.g., "No known allergy", "No known drug allergies"). Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'. If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.

        ShortCode that identifies the allergy or intolerance
        Comments

        It is strongly recommended that this element be populated using a terminology, where possible. For example, some terminologies used include RxNorm, SNOMED CT, DM+D, NDFRT, ICD-9, IDC-10, UNII, and ATC. Plain text should only be used if there is no appropriate terminology available. Additional details can be specified in the text.

        When a substance or product code is specified for the 'code' element, the "default" semantic context is that this is a positive statement of an allergy or intolerance (depending on the value of the 'type' element, if present) condition to the specified substance/product. In the corresponding SNOMED CT allergy model, the specified substance/product is the target (destination) of the "Causative agent" relationship.

        The 'substanceExposureRisk' extension is available as a structured and more flexible alternative to the 'code' element for making positive or negative allergy or intolerance statements. This extension provides the capability to make "no known allergy" (or "no risk of adverse reaction") statements regarding any coded substance/product (including cases when a pre-coordinated "no allergy to x" concept for that substance/product does not exist). If the 'substanceExposureRisk' extension is present, the AllergyIntolerance.code element SHALL be omitted.

        Control10..1
        This element is affected by the following invariants: ele-1
        BindingThe codes SHOULD be taken from For example codes, see UK Core Allergy Codehttp://hl7.org/fhir/ValueSet/allergyintolerance-code
        (preferred to https://fhir.hl7.org.uk/ValueSet/UKCore-AllergyCode)

        Type of the substance/product, allergy or intolerance condition, or negation/exclusion codes for reporting no known allergies.

        TypeCodeableConcept
        Is Modifierfalse
        Must Supporttrue
        Summarytrue
        Alternate NamesCode
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        20. AllergyIntolerance.patient
        Definition

        The patient who has the allergy or intolerance.

        ShortWho the sensitivity is for
        Comments

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

        Control1..1
        This element is affected by the following invariants: ele-1
        TypeReference(Patient, Patient)
        Is Modifierfalse
        Must Supporttrue
        Summarytrue
        Alternate NamesPatient
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        ref-1: SHALL have a contained resource if a local reference is provided (reference.startsWith('#').not() or (reference.substring(1).trace('url') in %rootResource.contained.id.trace('ids')))
        22. AllergyIntolerance.patient.identifier
        Definition

        An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.


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

        ShortAn identifier intended for computationLogical reference, when literal reference is not known
        Comments

        When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

        When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

        Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

        Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

        NoteThis is a business identifier, not a resource identifier (see discussion)
        Control0..1
        This element is affected by the following invariants: ele-1
        TypeIdentifier(NHS, HCSN and CHI Numbers)
        Is Modifierfalse
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        24. AllergyIntolerance.reaction
        Definition

        Details about each adverse reaction event linked to exposure to the identified substance.

        ShortAdverse Reaction Events linked to exposure to substance
        Control0..*
        This element is affected by the following invariants: ele-1
        TypeBackboneElement
        Is Modifierfalse
        Must Supporttrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        26. AllergyIntolerance.reaction.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..*
        This element is affected by the following invariants: ele-1
        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())
        ext-1: Must have either extensions or value[x], not both (extension.exists() != value.exists())
        28. AllergyIntolerance.reaction.manifestation
        Definition

        Clinical symptoms and/or signs that are observed or associated with the adverse reaction event.

        ShortClinical symptoms/signs associated with the Event
        Comments

        Manifestation can be expressed as a single word, phrase or brief description. For example: nausea, rash or no reaction. It is preferable that manifestation should be coded with a terminology, where possible. The values entered here may be used to display on an application screen as part of a list of adverse reactions, as recommended in the UK NHS CUI guidelines. Terminologies commonly used include, but are not limited to, SNOMED CT or ICD10.

        Control1..*
        This element is affected by the following invariants: ele-1
        BindingThe codes SHOULD be taken from For example codes, see UK Core Allergy Manifestationhttp://hl7.org/fhir/ValueSet/clinical-findings
        (preferred to https://fhir.hl7.org.uk/ValueSet/UKCore-AllergyManifestation)

        Clinical symptoms and/or signs that are observed or associated with an Adverse Reaction Event.

        TypeCodeableConcept
        Is Modifierfalse
        Alternate NamesSymptoms, Signs
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        30. AllergyIntolerance.reaction.severity
        Definition

        Clinical assessment of the severity of the reaction event as a whole, potentially considering multiple different manifestations.

        Shortmild | moderate | severe (of event as a whole)
        Comments

        It is acknowledged that this assessment is very subjective. There may be some specific practice domains where objective scales have been applied. Objective scales can be included in this model as extensions.

        Control0..1
        This element is affected by the following invariants: ele-1
        BindingThe codes SHALL be taken from AllergyIntoleranceSeverityhttp://hl7.org/fhir/ValueSet/reaction-event-severity|4.0.1
        (required to http://hl7.org/fhir/ValueSet/reaction-event-severity|4.0.1)

        Clinical assessment of the severity of a reaction event as a whole, potentially considering multiple different manifestations.

        Typecode
        Is Modifierfalse
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Must Supporttrue
        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. AllergyIntolerance
        Definition

        Risk of harmful or undesirable, physiological response which is unique to an individual and associated with exposure to a substance.

        ShortAllergy or Intolerance (generally: Risk of adverse reaction to a substance)
        Comments

        Substances include, but are not limited to: a therapeutic substance administered correctly at an appropriate dosage for the individual; food; material derived from plants or animals; or venom from insect stings.

        Control0..*
        Alternate NamesAllergy, Intolerance, Adverse Reaction
        Invariantsdom-2: If the resource is contained in another resource, it SHALL NOT contain nested Resources (contained.contained.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-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-6: A resource should have narrative for robust management (text.`div`.exists())
        dom-5: If a resource is contained in another resource, it SHALL NOT have a security label (contained.meta.security.empty())
        ait-1: AllergyIntolerance.clinicalStatus SHALL be present if verificationStatus is not entered-in-error. (verificationStatus.coding.where(system = 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification' and code = 'entered-in-error').exists() or clinicalStatus.exists())
        ait-2: AllergyIntolerance.clinicalStatus SHALL NOT be present if verification Status is entered-in-error (verificationStatus.coding.where(system = 'http://terminology.hl7.org/CodeSystem/allergyintolerance-verification' and code = 'entered-in-error').empty() or clinicalStatus.empty())
        2. AllergyIntolerance.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
        Summarytrue
        4. AllergyIntolerance.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
        This element is affected by the following invariants: ele-1
        TypeMeta
        Summarytrue
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        6. AllergyIntolerance.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
        This element is affected by the following invariants: ele-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. AllergyIntolerance.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
        This element is affected by the following invariants: ele-1
        BindingThe codes SHOULD be taken from CommonLanguages
        (preferred to http://hl7.org/fhir/ValueSet/languages)

        A human language.

        Additional BindingsPurpose
        AllLanguagesMax Binding
        Typecode
        Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        10. AllergyIntolerance.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
        This element is affected by the following invariants: ele-1
        TypeNarrative
        Alternate Namesnarrative, html, xhtml, display
        Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
        12. AllergyIntolerance.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
        Alternate Namesinline resources, anonymous resources, contained resources
        14. AllergyIntolerance.extension
        Definition

        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.

        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..*
        This element is affected by the following invariants: ele-1
        TypeExtension
        Standard StatusNormative (from Trial Use)
        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 AllergyIntolerance.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
        • value @ url
        • 16. AllergyIntolerance.extension:evidence
          Slice Nameevidence
          Definition

          A reference to results of investigations that confirmed the certainty of the diagnosis.

          ShortA reference to results of investigations that confirmed the certainty of the diagnosis.
          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..*
          This element is affected by the following invariants: ele-1
          TypeExtension(Extension UK Core Evidence) (Extension Type: Reference(DiagnosticReport))
          Standard StatusNormative (from Trial Use)
          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())
          18. AllergyIntolerance.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..*
          This element is affected by the following invariants: ele-1
          TypeExtension
          Is Modifiertrue because Modifier extensions are expected to modify the meaning or interpretation of the resource that contains them
          Standard StatusNormative (from Trial Use)
          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())
          SlicingThis element introduces a set of slices on AllergyIntolerance.modifierExtension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
          • value @ url
          • 20. AllergyIntolerance.identifier
            Definition

            Business identifiers assigned to this AllergyIntolerance by the performer or other systems which remain constant as the resource is updated and propagates from server to server.

            ShortExternal ids for this item
            Comments

            This is a business identifier, not a resource identifier (see discussion). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types. For example, multiple Patient and a Person resource instance might share the same social insurance number.

            NoteThis is a business identifier, not a resource identifier (see discussion)
            Control1..*
            This element is affected by the following invariants: ele-1
            TypeIdentifier
            Must Supporttrue
            Summarytrue
            Requirements

            Allows identification of the AllergyIntolerance as it is known by various participating systems and in a way that remains consistent across servers.

            Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
            SlicingThis element introduces a set of slices on AllergyIntolerance.identifier. The slices areUnordered and Closed, and can be differentiated using the following discriminators:
            • pattern @ system
            • 22. AllergyIntolerance.identifier:CommonResourceIdentifiers
              Slice NameCommonResourceIdentifiers
              Definition

              An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.

              ShortCommon Resource Identifiers
              Comments

              This is a business identifier, not a resource identifier (see discussion). It is best practice for the identifier to only appear on a single resource instance, however business practices may occasionally dictate that multiple resource instances with the same identifier can exist - possibly even with different resource types. For example, multiple Patient and a Person resource instance might share the same social insurance number.

              NoteThis is a business identifier, not a resource identifier (see discussion)
              Control0..*
              This element is affected by the following invariants: ele-1
              TypeIdentifier(Common Resource Identifiers)
              Is Modifierfalse
              Requirements

              Allows identification of the AllergyIntolerance as it is known by various participating systems and in a way that remains consistent across servers.

              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              24. AllergyIntolerance.clinicalStatus
              Definition

              The clinical status of the allergy or intolerance.

              Shortactive | inactive | resolved
              Comments

              Refer to discussion if clincalStatus is missing data. The data type is CodeableConcept because clinicalStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.

              Control0..1
              This element is affected by the following invariants: ele-1, ait-1, ait-2
              BindingThe codes SHALL be taken from AllergyIntoleranceClinicalStatusCodes
              (required to http://hl7.org/fhir/ValueSet/allergyintolerance-clinical|4.0.1)

              The clinical status of the allergy or intolerance.

              TypeCodeableConcept
              Is Modifiertrue because This element is labeled as a modifier because the status contains the codes inactive and resolved that mark the AllergyIntolerance as no longer active.
              Must Supporttrue
              Summarytrue
              Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
              26. AllergyIntolerance.clinicalStatus.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
              XML FormatIn the XML format, this property is represented as an attribute.
              28. AllergyIntolerance.clinicalStatus.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..*
              This element is affected by the following invariants: ele-1
              TypeExtension
              Standard StatusNormative (from Trial Use)
              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 AllergyIntolerance.clinicalStatus.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
              • value @ url
              • 30. AllergyIntolerance.clinicalStatus.extension:allergyIntoleranceEnd
                Slice NameallergyIntoleranceEnd
                Definition

                Supports the date when the allergy or intolerance was no longer valid, and/or, the reason why the allergy or intolerance is no longer valid.

                ShortSupports the date when the allergy or intolerance was no longer valid, and/or, the reason why the allergy or intolerance is no longer valid.
                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..1
                This element is affected by the following invariants: ele-1
                TypeExtension(Extension UK Core Allergy Intolerance End) (Complex Extension)
                Is Modifierfalse
                Standard StatusNormative (from Trial Use)
                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())
                32. AllergyIntolerance.clinicalStatus.coding
                Definition

                A reference to a code defined by a terminology system.

                ShortCode defined by a terminology system
                Comments

                Codes may be defined very casually in enumerations, or code lists, up to very formal definitions such as SNOMED CT - see the HL7 v3 Core Principles for more information. Ordering of codings is undefined and SHALL NOT be used to infer meaning. Generally, at most only one of the coding values will be labeled as UserSelected = true.

                Control0..*
                This element is affected by the following invariants: ele-1
                TypeCoding
                Summarytrue
                Requirements

                Allows for alternative encodings within a code system, and translations to other code systems.

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

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

                ShortPlain text representation of the concept
                Comments

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

                Control0..1
                This element is affected by the following invariants: ele-1
                Typestring
                Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                Summarytrue
                Requirements

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

                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                36. AllergyIntolerance.verificationStatus
                Definition

                Assertion about certainty associated with the propensity, or potential risk, of a reaction to the identified substance (including pharmaceutical product).

                Shortunconfirmed | confirmed | refuted | entered-in-error
                Comments

                The data type is CodeableConcept because verificationStatus has some clinical judgment involved, such that there might need to be more specificity than the required FHIR value set allows. For example, a SNOMED coding might allow for additional specificity.

                Control0..1
                This element is affected by the following invariants: ele-1, ait-1, ait-2
                BindingThe codes SHALL be taken from AllergyIntoleranceVerificationStatusCodes
                (required to http://hl7.org/fhir/ValueSet/allergyintolerance-verification|4.0.1)

                Assertion about certainty associated with a propensity, or potential risk, of a reaction to the identified substance.

                TypeCodeableConcept
                Is Modifiertrue because This element is labeled as a modifier because the status contains the codes refuted and entered-in-error that mark the AllergyIntolerance as not currently valid.
                Must Supporttrue
                Summarytrue
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                38. AllergyIntolerance.type
                Definition

                Identification of the underlying physiological mechanism for the reaction risk.

                Shortallergy | intolerance - Underlying mechanism (if known)
                Comments

                Allergic (typically immune-mediated) reactions have been traditionally regarded as an indicator for potential escalation to significant future risk. Contemporary knowledge suggests that some reactions previously thought to be immune-mediated are, in fact, non-immune, but in some cases can still pose a life threatening risk. It is acknowledged that many clinicians might not be in a position to distinguish the mechanism of a particular reaction. Often the term "allergy" is used rather generically and may overlap with the use of "intolerance" - in practice the boundaries between these two concepts might not be well-defined or understood. This data element is included nevertheless, because many legacy systems have captured this attribute. Immunologic testing may provide supporting evidence for the basis of the reaction and the causative substance, but no tests are 100% sensitive or specific for sensitivity to a particular substance. If, as is commonly the case, it is unclear whether the reaction is due to an allergy or an intolerance, then the type element should be omitted from the resource.

                Control0..1
                This element is affected by the following invariants: ele-1
                BindingThe codes SHALL be taken from AllergyIntoleranceType
                (required to http://hl7.org/fhir/ValueSet/allergy-intolerance-type|4.0.1)

                Identification of the underlying physiological mechanism for a Reaction Risk.

                Typecode
                Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                Summarytrue
                Alternate NamesCategory, Class
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                40. AllergyIntolerance.category
                Definition

                Category of the identified substance.

                Shortfood | medication | environment | biologic
                Comments

                This data element has been included because it is currently being captured in some clinical systems. This data can be derived from the substance where coding systems are used, and is effectively redundant in that situation. When searching on category, consider the implications of AllergyIntolerance resources without a category. For example, when searching on category = medication, medication allergies that don't have a category valued will not be returned. Refer to search for more information on how to search category with a :missing modifier to get allergies that don't have a category. Additionally, category should be used with caution because category can be subjective based on the sender.

                Control0..*
                This element is affected by the following invariants: ele-1
                BindingThe codes SHALL be taken from AllergyIntoleranceCategory
                (required to http://hl7.org/fhir/ValueSet/allergy-intolerance-category|4.0.1)

                Category of an identified substance associated with allergies or intolerances.

                Typecode
                Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                Summarytrue
                Alternate NamesCategory, Type, Reaction Type, Class
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                42. AllergyIntolerance.criticality
                Definition

                Estimate of the potential clinical harm, or seriousness, of the reaction to the identified substance.

                Shortlow | high | unable-to-assess
                Comments

                The default criticality value for any propensity to an adverse reaction should be 'Low Risk', indicating at the very least a relative contraindication to deliberate or voluntary exposure to the substance. 'High Risk' is flagged if the clinician has identified a propensity for a more serious or potentially life-threatening reaction, such as anaphylaxis, and implies an absolute contraindication to deliberate or voluntary exposure to the substance. If this element is missing, the criticality is unknown (though it may be known elsewhere). Systems that capture a severity at the condition level are actually representing the concept of criticality whereas the severity documented at the reaction level is representing the true reaction severity. Existing systems that are capturing both condition criticality and reaction severity may use the term "severity" to represent both. Criticality is the worst it could be in the future (i.e. situation-agnostic) whereas severity is situation-dependent.

                Control0..1
                This element is affected by the following invariants: ele-1
                BindingThe codes SHALL be taken from AllergyIntoleranceCriticality
                (required to http://hl7.org/fhir/ValueSet/allergy-intolerance-criticality|4.0.1)

                Estimate of the potential clinical harm, or seriousness, of a reaction to an identified substance.

                Typecode
                Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                Summarytrue
                Alternate NamesSeverity, Seriousness, Contra-indication, Risk
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                44. AllergyIntolerance.code
                Definition

                Code for an allergy or intolerance statement (either a positive or a negated/excluded statement). This may be a code for a substance or pharmaceutical product that is considered to be responsible for the adverse reaction risk (e.g., "Latex"), an allergy or intolerance condition (e.g., "Latex allergy"), or a negated/excluded code for a specific substance or class (e.g., "No latex allergy") or a general or categorical negated statement (e.g., "No known allergy", "No known drug allergies"). Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'. If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.

                ShortCode that identifies the allergy or intolerance
                Comments

                It is strongly recommended that this element be populated using a terminology, where possible. For example, some terminologies used include RxNorm, SNOMED CT, DM+D, NDFRT, ICD-9, IDC-10, UNII, and ATC. Plain text should only be used if there is no appropriate terminology available. Additional details can be specified in the text.

                When a substance or product code is specified for the 'code' element, the "default" semantic context is that this is a positive statement of an allergy or intolerance (depending on the value of the 'type' element, if present) condition to the specified substance/product. In the corresponding SNOMED CT allergy model, the specified substance/product is the target (destination) of the "Causative agent" relationship.

                The 'substanceExposureRisk' extension is available as a structured and more flexible alternative to the 'code' element for making positive or negative allergy or intolerance statements. This extension provides the capability to make "no known allergy" (or "no risk of adverse reaction") statements regarding any coded substance/product (including cases when a pre-coordinated "no allergy to x" concept for that substance/product does not exist). If the 'substanceExposureRisk' extension is present, the AllergyIntolerance.code element SHALL be omitted.

                Control1..1
                This element is affected by the following invariants: ele-1
                BindingThe codes SHOULD be taken from UK Core Allergy Code
                (preferred to https://fhir.hl7.org.uk/ValueSet/UKCore-AllergyCode)

                Type of the substance/product, allergy or intolerance condition, or negation/exclusion codes for reporting no known allergies.

                TypeCodeableConcept
                Must Supporttrue
                Summarytrue
                Alternate NamesCode
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                46. AllergyIntolerance.patient
                Definition

                The patient who has the allergy or intolerance.

                ShortWho the sensitivity is for
                Comments

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

                Control1..1
                This element is affected by the following invariants: ele-1
                TypeReference(Patient)
                Must Supporttrue
                Summarytrue
                Alternate NamesPatient
                Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                ref-1: SHALL have a contained resource if a local reference is provided (reference.startsWith('#').not() or (reference.substring(1).trace('url') in %rootResource.contained.id.trace('ids')))
                48. AllergyIntolerance.patient.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
                50. AllergyIntolerance.patient.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())
                SlicingThis element introduces a set of slices on AllergyIntolerance.patient.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                • value @ url
                • 52. AllergyIntolerance.patient.reference
                  Definition

                  A reference to a location at which the other resource is found. The reference may be a relative reference, in which case it is relative to the service base URL, or an absolute URL that resolves to the location where the resource is found. The reference may be version specific or not. If the reference is not to a FHIR RESTful server, then it should be assumed to be version specific. Internal fragment references (start with '#') refer to contained resources.

                  ShortLiteral reference, Relative, internal or absolute URL
                  Comments

                  Using absolute URLs provides a stable scalable approach suitable for a cloud/web context, while using relative/logical references provides a flexible approach suitable for use when trading across closed eco-system boundaries. Absolute URLs do not need to point to a FHIR RESTful server, though this is the preferred approach. If the URL conforms to the structure "/[type]/[id]" then it should be assumed that the reference is to a FHIR RESTful server.

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

                  The expected type of the target of the reference. If both Reference.type and Reference.reference are populated and Reference.reference is a FHIR URL, both SHALL be consistent.

                  The type is the Canonical URL of Resource Definition that is the type this reference refers to. References are URLs that are relative to http://hl7.org/fhir/StructureDefinition/ e.g. "Patient" is a reference to http://hl7.org/fhir/StructureDefinition/Patient. Absolute URLs are only allowed for logical models (and can only be used in references in logical models, not resources).

                  ShortType the reference refers to (e.g. "Patient")
                  Comments

                  This element is used to indicate the type of the target of the reference. This may be used which ever of the other elements are populated (or not). In some cases, the type of the target may be determined by inspection of the reference (e.g. a RESTful URL) or by resolving the target of the reference; if both the type and a reference is provided, the reference SHALL resolve to a resource of the same type as that specified.

                  Control0..1
                  BindingUnless not suitable, these codes SHALL be taken from ResourceType
                  (extensible to http://hl7.org/fhir/ValueSet/resource-types)

                  Aa resource (or, for logical models, the URI of the logical model).

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

                  An identifier - identifies some entity uniquely and unambiguously. Typically this is used for business identifiers.

                  ShortAn identifier intended for computation
                  Comments

                  When an identifier is provided in place of a reference, any system processing the reference will only be able to resolve the identifier to a reference if it understands the business context in which the identifier is used. Sometimes this is global (e.g. a national identifier) but often it is not. For this reason, none of the useful mechanisms described for working with references (e.g. chaining, includes) are possible, nor should servers be expected to be able resolve the reference. Servers may accept an identifier based reference untouched, resolve it, and/or reject it - see CapabilityStatement.rest.resource.referencePolicy.

                  When both an identifier and a literal reference are provided, the literal reference is preferred. Applications processing the resource are allowed - but not required - to check that the identifier matches the literal reference

                  Applications converting a logical reference to a literal reference may choose to leave the logical reference present, or remove it.

                  Reference is intended to point to a structure that can potentially be expressed as a FHIR resource, though there is no need for it to exist as an actual FHIR resource instance - except in as much as an application wishes to actual find the target of the reference. The content referred to be the identifier must meet the logical constraints implied by any limitations on what resource types are permitted for the reference. For example, it would not be legitimate to send the identifier for a drug prescription if the type were Reference(Observation|DiagnosticReport). One of the use-cases for Reference.identifier is the situation where no FHIR representation exists (where the type is Reference (Any).

                  NoteThis is a business identifier, not a resource identifier (see discussion)
                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypeIdentifier(NHS, HCSN and CHI Numbers)
                  Is Modifierfalse
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  58. AllergyIntolerance.patient.display
                  Definition

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

                  ShortText alternative for the resource
                  Comments

                  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.

                  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()))
                  60. AllergyIntolerance.encounter
                  Definition

                  The encounter when the allergy or intolerance was asserted.

                  ShortEncounter when the allergy or intolerance was asserted
                  Comments

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

                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypeReference(Encounter)
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  ref-1: SHALL have a contained resource if a local reference is provided (reference.startsWith('#').not() or (reference.substring(1).trace('url') in %rootResource.contained.id.trace('ids')))
                  62. AllergyIntolerance.onset[x]
                  Definition

                  Estimated or actual date, date-time, or age when allergy or intolerance was identified.

                  ShortWhen allergy or intolerance was identified
                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypeChoice of: dateTime, Age, Period, Range, string
                  [x] NoteSeeChoice of Data Typesfor further information about how to use [x]
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  64. AllergyIntolerance.recordedDate
                  Definition

                  The recordedDate represents when this particular AllergyIntolerance record was created in the system, which is often a system-generated date.

                  ShortDate first version of the resource instance was recorded
                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypedateTime
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  66. AllergyIntolerance.recorder
                  Definition

                  Individual who recorded the record and takes responsibility for its content.

                  ShortWho recorded the sensitivity
                  Comments

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

                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypeReference(Practitioner, PractitionerRole, Patient, RelatedPerson)
                  Alternate NamesAuthor
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  ref-1: SHALL have a contained resource if a local reference is provided (reference.startsWith('#').not() or (reference.substring(1).trace('url') in %rootResource.contained.id.trace('ids')))
                  68. AllergyIntolerance.asserter
                  Definition

                  The source of the information about the allergy that is recorded.

                  ShortSource of the information about the allergy
                  Comments

                  The recorder takes responsibility for the content, but can reference the source from where they got it.

                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypeReference(Patient, RelatedPerson, Practitioner, PractitionerRole)
                  Summarytrue
                  Alternate NamesSource, Informant
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  ref-1: SHALL have a contained resource if a local reference is provided (reference.startsWith('#').not() or (reference.substring(1).trace('url') in %rootResource.contained.id.trace('ids')))
                  70. AllergyIntolerance.lastOccurrence
                  Definition

                  Represents the date and/or time of the last known occurrence of a reaction event.

                  ShortDate(/time) of last known occurrence of a reaction
                  Comments

                  This date may be replicated by one of the Onset of Reaction dates. Where a textual representation of the date of last occurrence is required e.g. 'In Childhood, '10 years ago' the Comment element should be used.

                  Control0..1
                  This element is affected by the following invariants: ele-1
                  TypedateTime
                  Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  72. AllergyIntolerance.note
                  Definition

                  Additional narrative about the propensity for the Adverse Reaction, not captured in other fields.

                  ShortAdditional text not captured in other fields
                  Comments

                  For example: including reason for flagging a seriousness of 'High Risk'; and instructions related to future exposure or administration of the substance, such as administration within an Intensive Care Unit or under corticosteroid cover. The notes should be related to an allergy or intolerance as a condition in general and not related to any particular episode of it. For episode notes and descriptions, use AllergyIntolerance.event.description and AllergyIntolerance.event.notes.

                  Control0..*
                  This element is affected by the following invariants: ele-1
                  TypeAnnotation
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  74. AllergyIntolerance.reaction
                  Definition

                  Details about each adverse reaction event linked to exposure to the identified substance.

                  ShortAdverse Reaction Events linked to exposure to substance
                  Control0..*
                  This element is affected by the following invariants: ele-1
                  TypeBackboneElement
                  Must Supporttrue
                  Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                  76. AllergyIntolerance.reaction.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
                  XML FormatIn the XML format, this property is represented as an attribute.
                  78. AllergyIntolerance.reaction.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..*
                  This element is affected by the following invariants: ele-1
                  TypeExtension
                  Standard StatusNormative (from Trial Use)
                  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 AllergyIntolerance.reaction.extension. The slices areUnordered and Open, and can be differentiated using the following discriminators:
                  • value @ url
                  • 80. AllergyIntolerance.reaction.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..*
                    This element is affected by the following invariants: ele-1
                    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())
                    82. AllergyIntolerance.reaction.substance
                    Definition

                    Identification of the specific substance (or pharmaceutical product) considered to be responsible for the Adverse Reaction event. Note: the substance for a specific reaction may be different from the substance identified as the cause of the risk, but it must be consistent with it. For instance, it may be a more specific substance (e.g. a brand medication) or a composite product that includes the identified substance. It must be clinically safe to only process the 'code' and ignore the 'reaction.substance'. If a receiving system is unable to confirm that AllergyIntolerance.reaction.substance falls within the semantic scope of AllergyIntolerance.code, then the receiving system should ignore AllergyIntolerance.reaction.substance.

                    ShortSpecific substance or pharmaceutical product considered to be responsible for event
                    Comments

                    Coding of the specific substance (or pharmaceutical product) with a terminology capable of triggering decision support should be used wherever possible. The 'code' element allows for the use of a specific substance or pharmaceutical product, or a group or class of substances. In the case of an allergy or intolerance to a class of substances, (for example, "penicillins"), the 'reaction.substance' element could be used to code the specific substance that was identified as having caused the reaction (for example, "amoxycillin"). Duplication of the value in the 'code' and 'reaction.substance' elements is acceptable when a specific substance has been recorded in 'code'.

                    Control0..1
                    This element is affected by the following invariants: ele-1
                    BindingThe codes SHOULD be taken from UK Core Allergy Substance
                    (preferred to https://fhir.hl7.org.uk/ValueSet/UKCore-AllergySubstance)

                    Codes defining the type of the substance (including pharmaceutical products).

                    TypeCodeableConcept
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    84. AllergyIntolerance.reaction.manifestation
                    Definition

                    Clinical symptoms and/or signs that are observed or associated with the adverse reaction event.

                    ShortClinical symptoms/signs associated with the Event
                    Comments

                    Manifestation can be expressed as a single word, phrase or brief description. For example: nausea, rash or no reaction. It is preferable that manifestation should be coded with a terminology, where possible. The values entered here may be used to display on an application screen as part of a list of adverse reactions, as recommended in the UK NHS CUI guidelines. Terminologies commonly used include, but are not limited to, SNOMED CT or ICD10.

                    Control1..*
                    This element is affected by the following invariants: ele-1
                    BindingThe codes SHOULD be taken from UK Core Allergy Manifestation
                    (preferred to https://fhir.hl7.org.uk/ValueSet/UKCore-AllergyManifestation)

                    Clinical symptoms and/or signs that are observed or associated with an Adverse Reaction Event.

                    TypeCodeableConcept
                    Alternate NamesSymptoms, Signs
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    86. AllergyIntolerance.reaction.description
                    Definition

                    Text description about the reaction as a whole, including details of the manifestation if required.

                    ShortDescription of the event as a whole
                    Comments

                    Use the description to provide any details of a particular event of the occurred reaction such as circumstances, reaction specifics, what happened before/after. Information, related to the event, but not describing a particular care should be captured in the comment field. For example: at the age of four, the patient was given penicillin for strep throat and subsequently developed severe hives.

                    Control0..1
                    This element is affected by the following invariants: ele-1
                    Typestring
                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                    Alternate NamesNarrative, Text
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    88. AllergyIntolerance.reaction.onset
                    Definition

                    Record of the date and/or time of the onset of the Reaction.

                    ShortDate(/time) when manifestations showed
                    Control0..1
                    This element is affected by the following invariants: ele-1
                    TypedateTime
                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    90. AllergyIntolerance.reaction.severity
                    Definition

                    Clinical assessment of the severity of the reaction event as a whole, potentially considering multiple different manifestations.

                    Shortmild | moderate | severe (of event as a whole)
                    Comments

                    It is acknowledged that this assessment is very subjective. There may be some specific practice domains where objective scales have been applied. Objective scales can be included in this model as extensions.

                    Control0..1
                    This element is affected by the following invariants: ele-1
                    BindingThe codes SHALL be taken from AllergyIntoleranceSeverity
                    (required to http://hl7.org/fhir/ValueSet/reaction-event-severity|4.0.1)

                    Clinical assessment of the severity of a reaction event as a whole, potentially considering multiple different manifestations.

                    Typecode
                    Primitive ValueThis primitive element may be present, or absent, or replaced by an extension
                    Must Supporttrue
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    92. AllergyIntolerance.reaction.exposureRoute
                    Definition

                    Identification of the route by which the subject was exposed to the substance.

                    ShortHow the subject was exposed to the substance
                    Comments

                    Coding of the route of exposure with a terminology should be used wherever possible.

                    Control0..1
                    This element is affected by the following invariants: ele-1
                    BindingThe codes SHOULD be taken from UK Core Substance Or Product Administration Route
                    (preferred to https://fhir.hl7.org.uk/ValueSet/UKCore-SubstanceOrProductAdministrationRoute)

                    A coded concept describing the route or physiological path of administration of a therapeutic agent into or onto the body of a subject.

                    TypeCodeableConcept
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))
                    94. AllergyIntolerance.reaction.note
                    Definition

                    Additional text about the adverse reaction event not captured in other fields.

                    ShortText about event not captured in other fields
                    Comments

                    Use this field to record information indirectly related to a particular event and not captured in the description. For example: Clinical records are no longer available, recorded based on information provided to the patient by her mother and her mother is deceased.

                    Control0..*
                    This element is affected by the following invariants: ele-1
                    TypeAnnotation
                    Invariantsele-1: All FHIR elements must have a @value or children (hasValue() or (children().count() > id.count()))