4.1 Resource AllergyIntolerance - Content

4.1.1 Scope and Usage

A record of a clinical assessment of an allergy or intolerance; a propensity, or a potential risk to an individual, to have an adverse reaction on future exposure to the specified substance, or class of substance.

Where a propensity is identified, to record information or evidence about a reaction event that is characterised by any harmful or undesirable, physiological response that is specific to the individual, and triggered by exposure of an individual to the identified substance or class of substance.

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.

Note for Reviewers

Presently open issues for this resource:

• This resource represents a condition of susceptibility to a substance, with a list of supporting events and/or symptoms, and has no direct relationship to an event reporting framework; this will be re-assessed when adverse event reporting resource(s) and/or profiles are added to FHIR (not expected to happen prior to DSTU 2)
• Other HL7 models and the openEHR archetype have "exposure date" but this is not found in any surveyed systems, so this is left as an extension (more appropriate for adverse event reporting)

4.1.2 Boundaries and Relationships

This resource is used to provide a single place within the health record to document a range of clinical statements about adverse reactions, including:

• record a clinical assessment of the individual's propensity to a potential future reaction upon re-exposure
• record cumulative information about the reaction to each exposure, including 'no reaction' if appropriate

Use to record information about the positive presence of the risk of an adverse reaction:

• to support direct clinical care of an individual
• as part of a managed adverse reaction or allergy/intolerance list
• to support exchange of information about the propensity and events related to adverse reactions
• to inform adverse reaction reporting
• to assist computerised knowledge-based activities such as clinical decision support and alerts

Use to record information about adverse reactions to a broad range of substances, including: biological & blood products; incipients and excipients in medicinal preparations; foods; metal salts; and organic chemical compounds.

Adverse reactions may be:

• an allergy (immune mediated reaction - most commonly type I hypersensitivity)
• an intolerance (non-immune mediated reaction) - including pseudoallergic reactions, side effects, drug toxicities (e.g., to gentamicin), drug-drug interactions, food-drug interactions, and drug-disease interactions

In clinical practice distinguishing between allergic (immune-mediated) and intolerance (non-immune mediated) reactions is difficult and may not be practical. Often the term "allergy" is used in a rather generic sense which may overlap with the use of "intolerance" - in practice the boundaries between these two concepts may not be well-defined or understood. The term "intolerance" should be generally applied to reactions and to the propensity for future reactions where either the sensitivity is felt to not be on an immunologic basis or when the mechanism is unknown. Identification of the type of reaction is not a proxy for seriousness or risk of harm to the patient, which is better expressed by the manifestation in clinical practice.

The sensitivity in the case of either an allergy or intolerance is unique to the individual, and is distinguished from those reactions that are a property of the circumstance, such as toxicity of a food or drug, overdose, drug-drug, drug-food, or drug-disease interaction (which are reactions that would be expected to occur for any individual given the same circumstances).

The risk of an adverse reaction event or manifestation should not be recorded without identifying a proposed causative substance or class of substance. If there is uncertainty that a specific substance is the cause, this uncertainty can be recorded using the 'status' data element. If there are multiple possible substances that may have caused a reaction/manifestation, each substance should be recorded using a separate instance of this resource with the 'status' set to an initial state of 'unconfirmed' so that adverse reaction checking can be supported in clinical systems. If a substance, agent or class is later proven not to be the cause for a given reaction then the 'status' can be modified to 'refuted'.

This resource has been designed to allow recording of information about a specific substance (amoxicillin, oysters, or bee sting venom) or, alternatively, a class of substance (eg penicillins)). If a class of substance is recorded then identification of the exact substance can be recorded on a per exposure basis.

The scope of this FHIR resource has deliberately focused on identifying a pragmatic data set that are used in most clinical systems or will be suitable for most common clinical scenarios; extensions can be used to add additional detail if required. Examples of clinical situations where the extension may be required include: a detailed allergist/immunologist assessment, for reporting to regulatory bodies or use in a clinical trial.

The act of recording any adverse reaction in a health record involves the clinical assessment that a potential hazard exists for an individual if they are exposed to the same substance/agent/class in the future – that is, a relative contraindication - and, in the absence of additional information indicating a higher level of potential risk, the default 'criticality' value should be set to 'Low Risk'. If a clinician considers that it is not safe for the individual to be deliberately re-exposed to the substance/agent again, for example, following a manifestation of a life-threatening anaphylaxis, then the 'criticality' data element should be amended to 'High Risk'.

A formal adverse event report to regulatory bodies is a document that will contain a broad range of information in addition to the specific details about the adverse reaction. The report could utilise parts of this resource plus include additional data as required per jurisdiction.

An adverse reaction or allergy/intolerance list is a record of all identified propensities for an adverse reaction for the individual upon future exposure to the substance or class, plus provides potential access to the evidence provided by details about each reaction event, such as manifestation.

Valuable first-level information that could be presented to the clinician when they need to assess propensity for future reactions are:

• statements about previous clinical manifestations following exposure
• source of the information/reporter
• the 'criticality' flag

Second-level information can be drawn from each exposure event and links to additional detailed information such as history, examination and diagnoses stored elsewhere in the record, if it is available.

AllergyIntolerance and RiskAssessment

AllergyIntolerance describes a specific type of risk - propensity to reaction to a substance while RiskAssessment describes general risks to a subject, not generally based on a reaction.

AllergyIntolerance and Immunization.reaction

Immunization.reaction may be an indication of an allergy or intolerance. If this is deemed to be the case, a separate AllergyIntolerance record should be created to indicate it, as most systems will not query against past Immunization.reaction.

Misuse

• The allergy/intolerance list exists as a patient safety tool to inform decision support around ordering of medications and nutrition and to guide clinical treatment. Other reactions triggered by physical stimuli -- light, heat, cold, pressure, vibration, which may mimic allergic or intolerance reactions, should be recorded as Condition on the problem list, not using AllergyIntolerance.
• Not to be used to record adverse events, including failures of clinical process, interventions or products. For example: abnormal use or mistakes/errors made in maladministration of an agent or substance; incorrect dosage; mislabelling; harm or injury caused by an intervention or procedure; overdose/poisoning etc
• Not to be used as a proxy for an adverse event report. See above for how it may be used as one component of an adverse event report
• Not to be used for recording alerts. Alerts are handled using Flag or - where event-specific, DetectedIssue
• Not to be used for recording failed therapy

• Structure
• UML
• XML
• JSON
• All

Structure

Name	Flags	Card.	Type	Description & Constraints
AllergyIntolerance			DomainResource	Allergy or Intolerance (generally: Risk Of Adverse reaction to a substance)
identifier	Σ	0..*	Identifier	External Ids for this item
onset	Σ	0..1	dateTime	Date(/time) when manifestations showed
recordedDate	Σ	0..1	dateTime	When recorded
recorder	Σ	0..1	Reference(Practitioner | Patient)	Who recorded the sensitivity
patient	Σ	1..1	Reference(Patient)	Who the sensitivity is for
reporter	Σ	0..1	Reference(Patient | RelatedPerson | Practitioner)	Source of the information about the allergy
substance	Σ	1..1	CodeableConcept	Substance, (or class) considered to be responsible for risk AllergyIntolerance Substance and Negation Codes (Example)
status	?! Σ	0..1	code	active | unconfirmed | confirmed | inactive | resolved | refuted | entered-in-error AllergyIntoleranceStatus (Required)
criticality	Σ	0..1	code	CRITL | CRITH | CRITU AllergyIntoleranceCriticality (Required)
type	Σ	0..1	code	allergy | intolerance - Underlying mechanism (if known) AllergyIntoleranceType (Required)
category	Σ	0..1	code	food | medication | environment | other - Category of Substance AllergyIntoleranceCategory (Required)
lastOccurence	Σ	0..1	dateTime	Date(/time) of last known occurence of a reaction
note		0..1	Annotation	Additional text not captured in other fields
reaction		0..*	BackboneElement	Adverse Reaction Events linked to exposure to substance
substance	Σ	0..1	CodeableConcept	Specific substance considered to be responsible for event Substance Code (Example)
certainty	Σ	0..1	code	unlikely | likely | confirmed - clinical certainty about the specific substance AllergyIntoleranceCertainty (Required)
manifestation	Σ	1..*	CodeableConcept	Clinical symptoms/signs associated with the Event SNOMED CT Clinical Findings (Example)
description		0..1	string	Description of the event as a whole
onset	Σ	0..1	dateTime	Date(/time) when manifestations showed
severity	Σ	0..1	code	mild | moderate | severe (of event as a whole) AllergyIntoleranceSeverity (Required)
exposureRoute	Σ	0..1	CodeableConcept	How the subject was exposed to the substance SNOMED CT Route Codes (Example)
note		0..1	Annotation	Text about event not captured in other fields
Documentation for this format

<AllergyIntolerance xmlns="http://hl7.org/fhir"> 
 <!-- from Resource: id, meta, implicitRules, and language -->
 <!-- from DomainResource: text, contained, extension, and modifierExtension -->
 <identifier><!-- 0..* Identifier External Ids for this item --></identifier>
 <onset value="[dateTime]"/><!-- 0..1 Date(/time) when manifestations showed -->
 <recordedDate value="[dateTime]"/><!-- 0..1 When recorded -->
 <recorder><!-- 0..1 Reference(Practitioner|Patient) Who recorded the sensitivity --></recorder>
 <patient><!-- 1..1 Reference(Patient) Who the sensitivity is for --></patient>
 <reporter><!-- 0..1 Reference(Patient|RelatedPerson|Practitioner) Source of the information about the allergy --></reporter>
 <substance><!-- 1..1 CodeableConcept Substance, (or class) considered to be responsible for risk --></substance>
 <status value="[code]"/><!-- 0..1 active | unconfirmed | confirmed | inactive | resolved | refuted | entered-in-error -->
 <criticality value="[code]"/><!-- 0..1 CRITL | CRITH | CRITU -->
 <type value="[code]"/><!-- 0..1 allergy | intolerance - Underlying mechanism (if known) -->
 <category value="[code]"/><!-- 0..1 food | medication | environment | other - Category of Substance -->
 <lastOccurence value="[dateTime]"/><!-- 0..1 Date(/time) of last known occurence of a reaction -->
 <note><!-- 0..1 Annotation Additional text not captured in other fields --></note>
 <reaction>  <!-- 0..* Adverse Reaction Events linked to exposure to substance -->
  <substance><!-- 0..1 CodeableConcept Specific substance considered to be responsible for event --></substance>
  <certainty value="[code]"/><!-- 0..1 unlikely | likely | confirmed - clinical certainty about the specific substance -->
  <manifestation><!-- 1..* CodeableConcept Clinical symptoms/signs associated with the Event --></manifestation>
  <description value="[string]"/><!-- 0..1 Description of the event as a whole -->
  <onset value="[dateTime]"/><!-- 0..1 Date(/time) when manifestations showed -->
  <severity value="[code]"/><!-- 0..1 mild | moderate | severe (of event as a whole) -->
  <exposureRoute><!-- 0..1 CodeableConcept How the subject was exposed to the substance --></exposureRoute>
  <note><!-- 0..1 Annotation Text about event not captured in other fields --></note>
 </reaction>
</AllergyIntolerance>

{
  "resourceType" : "AllergyIntolerance",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "identifier" : [{ Identifier }], // External Ids for this item
  "onset" : "<dateTime>", // Date(/time) when manifestations showed
  "recordedDate" : "<dateTime>", // When recorded
  "recorder" : { Reference(Practitioner|Patient) }, // Who recorded the sensitivity
  "patient" : { Reference(Patient) }, // R!  Who the sensitivity is for
  "reporter" : { Reference(Patient|RelatedPerson|Practitioner) }, // Source of the information about the allergy
  "substance" : { CodeableConcept }, // R!  Substance, (or class) considered to be responsible for risk
  "status" : "<code>", // active | unconfirmed | confirmed | inactive | resolved | refuted | entered-in-error
  "criticality" : "<code>", // CRITL | CRITH | CRITU
  "type" : "<code>", // allergy | intolerance - Underlying mechanism (if known)
  "category" : "<code>", // food | medication | environment | other - Category of Substance
  "lastOccurence" : "<dateTime>", // Date(/time) of last known occurence of a reaction
  "note" : { Annotation }, // Additional text not captured in other fields
  "reaction" : [{ // Adverse Reaction Events linked to exposure to substance
    "substance" : { CodeableConcept }, // Specific substance considered to be responsible for event
    "certainty" : "<code>", // unlikely | likely | confirmed - clinical certainty about the specific substance
    "manifestation" : [{ CodeableConcept }], // R!  Clinical symptoms/signs associated with the Event
    "description" : "<string>", // Description of the event as a whole
    "onset" : "<dateTime>", // Date(/time) when manifestations showed
    "severity" : "<code>", // mild | moderate | severe (of event as a whole)
    "exposureRoute" : { CodeableConcept }, // How the subject was exposed to the substance
    "note" : { Annotation } // Text about event not captured in other fields
  }]
}

Structure

Name	Flags	Card.	Type	Description & Constraints
AllergyIntolerance			DomainResource	Allergy or Intolerance (generally: Risk Of Adverse reaction to a substance)
identifier	Σ	0..*	Identifier	External Ids for this item
onset	Σ	0..1	dateTime	Date(/time) when manifestations showed
recordedDate	Σ	0..1	dateTime	When recorded
recorder	Σ	0..1	Reference(Practitioner | Patient)	Who recorded the sensitivity
patient	Σ	1..1	Reference(Patient)	Who the sensitivity is for
reporter	Σ	0..1	Reference(Patient | RelatedPerson | Practitioner)	Source of the information about the allergy
substance	Σ	1..1	CodeableConcept	Substance, (or class) considered to be responsible for risk AllergyIntolerance Substance and Negation Codes (Example)
status	?! Σ	0..1	code	active | unconfirmed | confirmed | inactive | resolved | refuted | entered-in-error AllergyIntoleranceStatus (Required)
criticality	Σ	0..1	code	CRITL | CRITH | CRITU AllergyIntoleranceCriticality (Required)
type	Σ	0..1	code	allergy | intolerance - Underlying mechanism (if known) AllergyIntoleranceType (Required)
category	Σ	0..1	code	food | medication | environment | other - Category of Substance AllergyIntoleranceCategory (Required)
lastOccurence	Σ	0..1	dateTime	Date(/time) of last known occurence of a reaction
note		0..1	Annotation	Additional text not captured in other fields
reaction		0..*	BackboneElement	Adverse Reaction Events linked to exposure to substance
substance	Σ	0..1	CodeableConcept	Specific substance considered to be responsible for event Substance Code (Example)
certainty	Σ	0..1	code	unlikely | likely | confirmed - clinical certainty about the specific substance AllergyIntoleranceCertainty (Required)
manifestation	Σ	1..*	CodeableConcept	Clinical symptoms/signs associated with the Event SNOMED CT Clinical Findings (Example)
description		0..1	string	Description of the event as a whole
onset	Σ	0..1	dateTime	Date(/time) when manifestations showed
severity	Σ	0..1	code	mild | moderate | severe (of event as a whole) AllergyIntoleranceSeverity (Required)
exposureRoute	Σ	0..1	CodeableConcept	How the subject was exposed to the substance SNOMED CT Route Codes (Example)
note		0..1	Annotation	Text about event not captured in other fields
Documentation for this format

UML Diagram

XML Template

<AllergyIntolerance xmlns="http://hl7.org/fhir"> 
 <!-- from Resource: id, meta, implicitRules, and language -->
 <!-- from DomainResource: text, contained, extension, and modifierExtension -->
 <identifier><!-- 0..* Identifier External Ids for this item --></identifier>
 <onset value="[dateTime]"/><!-- 0..1 Date(/time) when manifestations showed -->
 <recordedDate value="[dateTime]"/><!-- 0..1 When recorded -->
 <recorder><!-- 0..1 Reference(Practitioner|Patient) Who recorded the sensitivity --></recorder>
 <patient><!-- 1..1 Reference(Patient) Who the sensitivity is for --></patient>
 <reporter><!-- 0..1 Reference(Patient|RelatedPerson|Practitioner) Source of the information about the allergy --></reporter>
 <substance><!-- 1..1 CodeableConcept Substance, (or class) considered to be responsible for risk --></substance>
 <status value="[code]"/><!-- 0..1 active | unconfirmed | confirmed | inactive | resolved | refuted | entered-in-error -->
 <criticality value="[code]"/><!-- 0..1 CRITL | CRITH | CRITU -->
 <type value="[code]"/><!-- 0..1 allergy | intolerance - Underlying mechanism (if known) -->
 <category value="[code]"/><!-- 0..1 food | medication | environment | other - Category of Substance -->
 <lastOccurence value="[dateTime]"/><!-- 0..1 Date(/time) of last known occurence of a reaction -->
 <note><!-- 0..1 Annotation Additional text not captured in other fields --></note>
 <reaction>  <!-- 0..* Adverse Reaction Events linked to exposure to substance -->
  <substance><!-- 0..1 CodeableConcept Specific substance considered to be responsible for event --></substance>
  <certainty value="[code]"/><!-- 0..1 unlikely | likely | confirmed - clinical certainty about the specific substance -->
  <manifestation><!-- 1..* CodeableConcept Clinical symptoms/signs associated with the Event --></manifestation>
  <description value="[string]"/><!-- 0..1 Description of the event as a whole -->
  <onset value="[dateTime]"/><!-- 0..1 Date(/time) when manifestations showed -->
  <severity value="[code]"/><!-- 0..1 mild | moderate | severe (of event as a whole) -->
  <exposureRoute><!-- 0..1 CodeableConcept How the subject was exposed to the substance --></exposureRoute>
  <note><!-- 0..1 Annotation Text about event not captured in other fields --></note>
 </reaction>
</AllergyIntolerance>

JSON Template

{
  "resourceType" : "AllergyIntolerance",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "identifier" : [{ Identifier }], // External Ids for this item
  "onset" : "<dateTime>", // Date(/time) when manifestations showed
  "recordedDate" : "<dateTime>", // When recorded
  "recorder" : { Reference(Practitioner|Patient) }, // Who recorded the sensitivity
  "patient" : { Reference(Patient) }, // R!  Who the sensitivity is for
  "reporter" : { Reference(Patient|RelatedPerson|Practitioner) }, // Source of the information about the allergy
  "substance" : { CodeableConcept }, // R!  Substance, (or class) considered to be responsible for risk
  "status" : "<code>", // active | unconfirmed | confirmed | inactive | resolved | refuted | entered-in-error
  "criticality" : "<code>", // CRITL | CRITH | CRITU
  "type" : "<code>", // allergy | intolerance - Underlying mechanism (if known)
  "category" : "<code>", // food | medication | environment | other - Category of Substance
  "lastOccurence" : "<dateTime>", // Date(/time) of last known occurence of a reaction
  "note" : { Annotation }, // Additional text not captured in other fields
  "reaction" : [{ // Adverse Reaction Events linked to exposure to substance
    "substance" : { CodeableConcept }, // Specific substance considered to be responsible for event
    "certainty" : "<code>", // unlikely | likely | confirmed - clinical certainty about the specific substance
    "manifestation" : [{ CodeableConcept }], // R!  Clinical symptoms/signs associated with the Event
    "description" : "<string>", // Description of the event as a whole
    "onset" : "<dateTime>", // Date(/time) when manifestations showed
    "severity" : "<code>", // mild | moderate | severe (of event as a whole)
    "exposureRoute" : { CodeableConcept }, // How the subject was exposed to the substance
    "note" : { Annotation } // Text about event not captured in other fields
  }]
}