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

Presntly 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)
• There is no "didNotOccur" flag on the event. Is this necessary? (not found in any surveyed systems)
• 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; metal salts; and organic chemical compounds.

Adverse reactions may be:

• an immune mediated reaction - Types I-VI (including allergic reactions and hypersensitivities)
• a non-immune mediated reaction - including pseudoallergic reactions, side effects, intolerances, drug toxicities (eg to Gentamicin), drug-drug interactions, food-drug interactions, and drug-disease interactions

In clinical practice distinguishing between immune-mediated and non-immune mediated reactions is difficult and often not practical. 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 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 the default 'Seriousness' value should be set to 'Low'. 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 'Seriousness' data element should be amended to 'High'.

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.

Misuse

• Not to be used for recording physiological reactions to physical agents, such as heat, cold, sunlight, vibration, exercise activity, by infectious agents or food contaminants. Use Condition instead
• 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
• 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
recordedDate	Σ	0..1	dateTime	When recorded
recorder	Σ	0..1	Practitioner | Patient	Who recorded the sensitivity
subject	Σ	1..1	Patient	Who the sensitivity is for
substance	Σ	1..1	CodeableConcept	Substance, (or class) considered to be responsible for risk SubstanceType (Example)
status	M Σ	0..1	code	unconfirmed | confirmed | resolved | refuted AllergyIntoleranceStatus (Required)
criticality	Σ	0..1	code	low | high | unassessible - Estimated potential clinical harm AllergyIntoleranceCriticality (Required)
type	Σ	0..1	code	immune | non-immune - Underlying mechanism (if known) AllergyIntoleranceType (Required)
category	Σ	0..1	code	food | medication | environment - Category of Substance AllergyIntoleranceCategory (Required)
lastOccurence	Σ	0..1	dateTime	Date(/time) of last known occurence of a reaction
comment		0..1	string	Additional text not captured in other fields
event		0..*	Element	Adverse Reaction Events linked to exposure to substance
substance	Σ	0..1	CodeableConcept	Specific substance considered to be responsible for event SubstanceType (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 Manifestation (Example)
description		0..1	string	Description of the event as a whole
onset	Σ	0..1	dateTime	Date(/time) when manifestations showed
duration		0..1	Duration	How long Manifestations persisted
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 RouteOfAdministration (Example)
comment		0..1	string	Text about event not captured in other fields

<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>
 <recordedDate value="[dateTime]"/><!-- 0..1 When recorded -->
 <recorder><!-- 0..1 Reference(Practitioner|Patient) Who recorded the sensitivity --></recorder>
 <subject><!-- 1..1 Reference(Patient) Who the sensitivity is for --></subject>
 <substance><!-- 1..1 CodeableConcept Substance, (or class) considered to be responsible for risk --></substance>
 <status value="[code]"/><!-- 0..1 unconfirmed | confirmed | resolved | refuted -->
 <criticality value="[code]"/><!-- 0..1 low | high | unassessible - Estimated potential clinical harm -->
 <type value="[code]"/><!-- 0..1 immune | non-immune - Underlying mechanism (if known) -->
 <category value="[code]"/><!-- 0..1 food | medication | environment - Category of Substance -->
 <lastOccurence value="[dateTime]"/><!-- 0..1 Date(/time) of last known occurence of a reaction -->
 <comment value="[string]"/><!-- 0..1 Additional text not captured in other fields -->
 <event>  <!-- 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 -->
  <duration><!-- 0..1 Duration How long Manifestations persisted --></duration>
  <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>
  <comment value="[string]"/><!-- 0..1 Text about event not captured in other fields -->
 </event>
</AllergyIntolerance>

{
  "resourceType" : "AllergyIntolerance",
  // from Resource: id, meta, implicitRules, and language
  // from DomainResource: text, contained, extension, and modifierExtension
  "identifier" : [{ Identifier }], // External Ids for this item
  "recordedDate" : "<dateTime>", // When recorded
  "recorder" : { Reference(Practitioner|Patient) }, // Who recorded the sensitivity
  "subject" : { Reference(Patient) }, // R! Who the sensitivity is for
  "substance" : { CodeableConcept }, // R! Substance, (or class) considered to be responsible for risk
  "status" : "<code>", // unconfirmed | confirmed | resolved | refuted
  "criticality" : "<code>", // low | high | unassessible - Estimated potential clinical harm
  "type" : "<code>", // immune | non-immune - Underlying mechanism (if known)
  "category" : "<code>", // food | medication | environment - Category of Substance
  "lastOccurence" : "<dateTime>", // Date(/time) of last known occurence of a reaction
  "comment" : "<string>", // Additional text not captured in other fields
  "event" : [{ // 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
    "duration" : { Duration }, // How long Manifestations persisted
    "severity" : "<code>", // mild | moderate | severe (of event as a whole)
    "exposureRoute" : { CodeableConcept }, // How the subject was exposed to the substance
    "comment" : "<string>" // 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
recordedDate	Σ	0..1	dateTime	When recorded
recorder	Σ	0..1	Practitioner | Patient	Who recorded the sensitivity
subject	Σ	1..1	Patient	Who the sensitivity is for
substance	Σ	1..1	CodeableConcept	Substance, (or class) considered to be responsible for risk SubstanceType (Example)
status	M Σ	0..1	code	unconfirmed | confirmed | resolved | refuted AllergyIntoleranceStatus (Required)
criticality	Σ	0..1	code	low | high | unassessible - Estimated potential clinical harm AllergyIntoleranceCriticality (Required)
type	Σ	0..1	code	immune | non-immune - Underlying mechanism (if known) AllergyIntoleranceType (Required)
category	Σ	0..1	code	food | medication | environment - Category of Substance AllergyIntoleranceCategory (Required)
lastOccurence	Σ	0..1	dateTime	Date(/time) of last known occurence of a reaction
comment		0..1	string	Additional text not captured in other fields
event		0..*	Element	Adverse Reaction Events linked to exposure to substance
substance	Σ	0..1	CodeableConcept	Specific substance considered to be responsible for event SubstanceType (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 Manifestation (Example)
description		0..1	string	Description of the event as a whole
onset	Σ	0..1	dateTime	Date(/time) when manifestations showed
duration		0..1	Duration	How long Manifestations persisted
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 RouteOfAdministration (Example)
comment		0..1	string	Text about event not captured in other fields

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>
 <recordedDate value="[dateTime]"/><!-- 0..1 When recorded -->
 <recorder><!-- 0..1 Reference(Practitioner|Patient) Who recorded the sensitivity --></recorder>
 <subject><!-- 1..1 Reference(Patient) Who the sensitivity is for --></subject>
 <substance><!-- 1..1 CodeableConcept Substance, (or class) considered to be responsible for risk --></substance>
 <status value="[code]"/><!-- 0..1 unconfirmed | confirmed | resolved | refuted -->
 <criticality value="[code]"/><!-- 0..1 low | high | unassessible - Estimated potential clinical harm -->
 <type value="[code]"/><!-- 0..1 immune | non-immune - Underlying mechanism (if known) -->
 <category value="[code]"/><!-- 0..1 food | medication | environment - Category of Substance -->
 <lastOccurence value="[dateTime]"/><!-- 0..1 Date(/time) of last known occurence of a reaction -->
 <comment value="[string]"/><!-- 0..1 Additional text not captured in other fields -->
 <event>  <!-- 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 -->
  <duration><!-- 0..1 Duration How long Manifestations persisted --></duration>
  <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>
  <comment value="[string]"/><!-- 0..1 Text about event not captured in other fields -->
 </event>
</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
  "recordedDate" : "<dateTime>", // When recorded
  "recorder" : { Reference(Practitioner|Patient) }, // Who recorded the sensitivity
  "subject" : { Reference(Patient) }, // R! Who the sensitivity is for
  "substance" : { CodeableConcept }, // R! Substance, (or class) considered to be responsible for risk
  "status" : "<code>", // unconfirmed | confirmed | resolved | refuted
  "criticality" : "<code>", // low | high | unassessible - Estimated potential clinical harm
  "type" : "<code>", // immune | non-immune - Underlying mechanism (if known)
  "category" : "<code>", // food | medication | environment - Category of Substance
  "lastOccurence" : "<dateTime>", // Date(/time) of last known occurence of a reaction
  "comment" : "<string>", // Additional text not captured in other fields
  "event" : [{ // 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
    "duration" : { Duration }, // How long Manifestations persisted
    "severity" : "<code>", // mild | moderate | severe (of event as a whole)
    "exposureRoute" : { CodeableConcept }, // How the subject was exposed to the substance
    "comment" : "<string>" // Text about event not captured in other fields
  }]
}