The FHIR R4 AllergyIntolerance resource captures information about a patient’s allergies or intolerances to substances such as medications, foods, or environmental agents. This information helps support safe clinical decision-making by documenting known adverse sensitivities and reactions.

Health Gorilla exposes AllergyIntolerance as part of its FHIR R4 API to support patient-centric clinical data access.

Use Cases

Retrieving a patient’s known allergies prior to prescribing medications
Recording newly identified allergies during patient intake or clinical encounters
Reviewing allergy history as part of longitudinal patient records

Scope and Behavior

This documentation describes the FHIR R4 API interface for AllergyIntolerance. Health Gorilla’s platform may use additional internal services and data standards to acquire, normalize, and route clinical information. Only the FHIR R4–exposed behavior is documented here.

Health Gorilla supports a subset of the HL7 FHIR R4 AllergyIntolerance resource. Not all optional elements defined in the HL7 specification may be stored, indexed, or returned. Unsupported or unrecognized elements may be ignored or normalized during processing.

In Health Gorilla, AllergyIntolerance is most commonly accessed as part of patient record retrieval workflows, where allergy data is aggregated from connected clinical sources and normalized for longitudinal review. This resource supports medication safety, care coordination, and clinical review use cases by exposing known allergy and intolerance information alongside other patient clinical data.

Authentication

All requests to the FHIR R4 API require OAuth 2.0 authentication using a bearer token. Unauthorized requests return a 401 Unauthorized response.

Required Scopes

allergyintolerance.read for GET
allergyintolerance.write for POST, PUT, and DELETE

For details on authentication and token acquisition, see OAuth 2.0 Authentication.

Search Behavior

Searches are scoped to the authenticated tenant.
The patient parameter is required for patient-scoped searches and is recommended for most search use cases.
Results are returned as a FHIR Bundle.
Pagination may be applied. Use standard FHIR pagination links (Bundle.link) to retrieve additional result pages.

Note: The parameters listed below are not exhaustive and reflect commonly used fields in typical Health Gorilla workflows. Supported parameters and behavior may vary by configuration.

Frequently Used Search Parameters

Parameter	Description	Example Values	FHIR Data Type
`patient`	Filters by patient	`Patient/{id}`	`Reference`
`clinicalStatus`	Filters by current allergy status	`active`	`token`
`verificationStatus`	Filters by level of certainty	`confirmed`	`token`
`recordedDate`	Filters by date recorded	`ge2022-01-01`, `le2023-12-31`	`date`
`category`	Filters by allergen category	`food`, `medication`	`token`
`code`	Filters by allergen substance	SNOMED CT, RxNorm codes	`token`
`recorder`	Filters by who recorded the allergy	`Practitioner/{id}`	`Reference`
`criticality`	Filters by potential severity	`high`	`token`
`onset`	Filters by onset date	`ge2020-01-01`	`date`
`lastOccurrence`	Filters by most recent reaction date	`le2024-12-31`	`date`

Commonly Returned Resource Attributes

Attribute	Description	Example Values	FHIR Data Type
`patient`	Patient who has the allergy or intolerance	`Patient/{id}`	`Reference(Patient)`
`code`	Allergen or substance	SNOMED CT or RxNorm codes	`CodeableConcept`
`type`	Type of sensitivity	`allergy`, `intolerance`	`code`
`category`	Allergen category	`food`, `medication`	`code[]`
`criticality`	Potential severity if exposed	`high`	`code`
`clinicalStatus`	Current status	`active`	`CodeableConcept`
`verificationStatus`	Certainty of allergy	`confirmed`	`CodeableConcept`
`onset`	When the allergy began	`YYYY-MM-DD`	`dateTime`, `Age`, `Period`
`recordedDate`	When recorded	`YYYY-MM-DD`	`dateTime`
`lastOccurrence`	Most recent reaction	`YYYY-MM-DD`	`dateTime`
`recorder`	Who recorded the allergy	`Practitioner/{id}`	`Reference`
`reaction.manifestation`	Reaction symptoms	`hives`, `dyspnea`	`CodeableConcept[]`
`reaction.severity`	Reaction severity	`mild`, `moderate`, `severe`	`code`
`reaction.substance`	Specific reaction substance	`penicillin G`	`CodeableConcept`
`reaction.description`	Text description	Free text	`string`

Notifications

The FHIR R4 API does not provide direct resource-change subscriptions for AllergyIntolerance. Changes to allergy information may surface through broader notification workflows, depending on enabled Health Gorilla products and configuration.

Error Handling

All AllergyIntolerance operations use standard Health Gorilla error handling and return a FHIR OperationOutcome resource for structured error details. For more information, go to Error Handling.

Additional Resources

HL7 FHIR AllergyIntolerance