Overview: Resources and Interactions Overview: API Searches
Opala FHIR Documentation
© 2021 Opala. All Rights Reserved.
Version 1.0
© 2021 Opala. All Rights Reserved.
Version 1.0
The AllergyIntolerance resource provides a single place within the health record to document a range of clinical statements about adverse reactions associated with exposure to a substance.
Where a potential risk is identified, the AllergyIntolerance resource enables you to record information or evidence about a reaction event characterized by any harmful or undesirable physiological response specific to the individual and triggered by exposure to the identified substance.
An adverse reaction can be an allergy or an intolerance.
Often the term “allergy” is used generically and may overlap with the term “intolerance”. In clinical practice distinguishing between allergy and intolerance is difficult and might not be practical. The boundaries between these concepts might not be well-defined or understood.
For the purposes of FHIR, an allergy is typically type I hypersensitivity, plus other “allergy-like” reactions, including pseudoallergy. An intolerance is typically a non-immune adverse reaction that is not determined or perceived to be allergic or “allergy-like.” To some extent, intolerances are idiosyncratic and/or individually specific. That is, they are not reactions that are expected to occur with most or all patients given similar circumstances.
If it is not possible to determine whether a particular adverse reaction is an allergy or an intolerance, the type element should be omitted from the resource.
If there is uncertainty that a specific substance is the cause of an adverse reaction, this uncertainty can be recorded using the verificationStatus data element. If there are multiple possible substances that may have caused a reaction, each substance should be recorded using a separate instance of this resource with the verificationStatus element 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, the verificationStatus can be modified to refuted.
In the absence of additional information indicating a higher level of potential risk from an adverse reaction, 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/product again, the criticality data element should be amended to High Risk.
An 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, since most systems will not query against past immunization.reactions.
The allergy/intolerance list exists as a patient safety tool to inform decision support for ordering medications and nutrition, and to guide clinical treatment. Other reactions triggered by physical stimuli may mimic allergic or intolerance reactions; however, these should be recorded using the Condition resource on the problem list, not using the AllergyIntolerance resource.
The AllergyIntolerance resource should:
Note: Alerts are handled using a Flag resource or, where event-specific, a DetectedIssue resource.
Systems that only support one notion will have to determine whether what they’re capturing is criticality or severity and map to the appropriate place. Criticality refers to the likelihood the allergy/intolerance could result in significant harm. Severity refers to the degree of manifestation of the reaction symptom.
Systems may use the List.emptyReason when a statement is about the full scope of the list. However, it is generally preferred to use a code for “No known allergies” so that all allergy data will be available and queryable from AllergyIntolerance resource instances.
Allergies with the verificationStatus entered-in-error indicates that the allergy or intolerance statement was entered by mistake and therefore is invalid.
Allergies with the verificationStatus refuted must be displayed to indicate that a reaction to a substance has been ruled out with the high level of clinical certainty.
Note: If a new allergy is discovered, the negated allergy record must be updated with the "refuted" verificationStatus - to ensure that systems referring to this record are aware that this is no longer true.
The AllergyIntolerance resource is referenced by these resources:
The US Core AllergyIntolerance profile sets the minimum expectations for the AllergyIntolerance resource to record, search, and fetch allergies/adverse reactions associated with a patient. It identifies the mandatory core elements, extensions, vocabularies, and value sets which are present in the AllergyIntolerance resource when using the profile.
The following search parameters and search parameter combinations shall be supported.
GET [base]/AllergyIntolerance?patient=[reference]
The following search parameter combinations should be supported.
GET [base]/AllergyIntolerance?patient=[reference]&clinical-status={system|}[code]
resource. for the elements in the AllergyIntolerance resource for the AllergyIntolerance resource for the AllergyIntolerance resource for the AllergyIntolerance resource for the AllergyIntolerance resource for AllergyIntolerance (3.6.1) for AllergyIntolerance (3.6.0.1)