Short answer: AllergyIntolerance is the FHIR resource for a risk of a harmful reaction to a substance: a medicine, a food, something in the environment. It records what the substance is, whether it is an allergy or an intolerance, how dangerous a future reaction could be (criticality) and the reactions that happened, each with its own severity.
Key elements
- clinicalStatus: active, inactive, resolved.
- verificationStatus: unconfirmed, confirmed, refuted, entered-in-error.
- type: allergy or intolerance.
- category: food, medication, environment, biologic.
- criticality: low, high or unable-to-assess, the risk of a future serious reaction.
- code: the substance or the allergy, usually SNOMED CT (allergy to penicillin is 91936005).
- reaction: the manifestation (for example hives), its severity (mild, moderate, severe) and onset.
Criticality is about the future; severity is about a past reaction. Mixing them is the most common mistake.
Example (FHIR R4)
{
"resourceType": "AllergyIntolerance",
"clinicalStatus": {"coding": [{"system": "http://terminology.hl7.org/CodeSystem/allergyintolerance-clinical", "code": "active"}]},
"verificationStatus": {"coding": [{"system": "http://terminology.hl7.org/CodeSystem/allergyintolerance-verification", "code": "confirmed"}]},
"type": "allergy",
"category": ["medication"],
"criticality": "high",
"code": {"coding": [{"system": "http://snomed.info/sct", "code": "91936005", "display": "Allergy to penicillin"}]},
"patient": {"reference": "Patient/example"},
"reaction": [{"manifestation": [{"text": "Hives"}], "severity": "moderate"}]
}
In Anpheros
In Anpheros, allergies sit at the top of each person's record, on the emergency card and in the International Patient Summary, stored as AllergyIntolerance resources. Our patient guide on the family's allergies shows the app side; developers can read them through the FHIR API.
Related pages
Sources
Frequently asked questions
What is the difference between criticality and severity?
Criticality is the potential seriousness of a future reaction; severity describes how bad a reaction that happened was.
Should I record an intolerance as an allergy?
No. Use type: intolerance; it tells other clinicians the reaction is not immune-mediated.
Which code system is used for allergies?
SNOMED CT is the most common; medicines can also be coded with RxNorm or ATC for the substance.
How do I record "no known allergies"?
With a specific code for no known allergy (the IPS defines how), not by leaving the list empty, which means unknown.
Try it free in the sandbox
Your first FHIR call in 5 minutes. An HL7 FHIR R4 API with the patient's consent built in: try it in the sandbox, then connect your own app or clinic system.
Free · 30 synthetic patients · no card
Anpheros builds a medical record that the patient controls and can share with any clinic, on an HL7 FHIR R4 platform, based in the EU. These guides help you understand and organise your health; they do not replace your doctor.
About Anpheros →
AnpherosThe more you log, the clearer your record
Your health history in one place, under your control.
Free · Works in your browser · No card
