Common CQL Artifacts for FHIR (US-Based), published by HL7 International / Clinical Decision Support. This guide is not an authorized publication; it is the continuous build for version 1.0.0-ballot built by the FHIR (HL7® FHIR® Standard) CI Build. This version is based on the current content of https://github.com/HL7/us-cql-ig/ and changes regularly. See the Directory of published versions

Allergy Patterns

US Core defines US Core Allergy Intolerance.

This profile is used to capture allergies / adverse reactions associated with a patient. By default, the primary terminology filter for AllergyIntolerance is code.

The codes come from a set of common substances for allergy documentation in SNOMED and RXNORM: https://vsac.nlm.nih.gov/valueset/2.16.840.1.113762.1.4.1186.8/expansion).

Modifier Elements

The AllergyIntolerance resource defines the following modifier elements:

• clinicalStatus
• verificationStatus

Note that neither of these elements are required, but both are must support, and have a required binding. As such the USCoreCommon library defines functions such as isActive() for assessing these statuses. Further examples are provided in the "Common Elements" section below.

Search Parameters

USCore requires searching by:

• patient

In addition, servers may support searching by:

• clinical-status

NOTE: For discussion on how to manage search parameters with terminology, see the Terminology Considerations discussion in the Architectural Guidance topic.

NOTE: For discussion on how to manage optional search parameters, see the Performant Data Access discussion in the Architectural Guidance topic.

Cross-Version Considerations

There are no significant differences between the 3.1.1, 6.1.0, and 7.0.0 versions of this profile.

Common Elements and Functions

Current allergies

To get all confirmed active allergies, UCE."Active Confirmed Allergies and Intolerances" can be used.

Current allergies to specific substances can make use of the terminology filter as part of the retrieve:

define "Statin Allergy Intolerance":
  [USCore."AllergyIntolerance": "Statin Allergen"] StatinAllergyIntolerance
    where StatinAllergyIntolerance.isActive()

NOTE: Because the AllergyIntolerance profile does not constraint the values of the clinicalStatus or verificationStatus elements, authors must consider the possible values of these elements to ensure the expression matches intent.

In retrospective cases, the logic will be evaluated on data that exists at the time of evaluation. This means that while a given allergy/intolerance may have been active during the retrospective period, it might no longer be active when the logic is evaluated.

No known allergies

To check if a patient has confirmed they have no known allergies, use UCE."No Known Allergies (Confirmed)". This will check for SNOMED 716186003 (No known allergy (situation)) as advised in US Core.

US Core also supports documenting UCE."No Known Allergies (Not Asked)", which also uses the No known allergy (situation) SNOMED code, but the instance uses the uncomfirmed verification status.

Contrast dye allergy:

Ordering HeadMRI vs HeadCT because patient has allergy to CT dye

ICD-10-CM Code for Radiographic dye allergy status Z91.041

Egg allergy:

ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification)
Z91.012 – Allergy to eggs
T78.1XXA – Other adverse food reactions, not elsewhere classified, initial encounter
T78.1XXD – Other adverse food reactions, not elsewhere classified, subsequent encounter
T78.1XXS – Other adverse food reactions, not elsewhere classified, sequela
Z91.018 – Allergy to other foods
SNOMED CT (Systematized Nomenclature of Medicine – Clinical Terms)
91934008 – Egg allergy
281784008 – Egg intolerance
293982008 – Anaphylaxis due to egg
LOINC (Logical Observation Identifiers Names and Codes)
6096-8 – Egg IgE [Mass/volume] in Serum
6241-0 – Egg white IgE [Mass/volume] in Serum
7286-1 – Egg yolk IgE [Mass/volume] in Serum

Nut allergy:

ICD-10-CM Codes for Nut Allergies
ICD-10-CM classifies food allergies, including nut allergies, under T78.0–T78.1 and Z91.01 series:
T78.01XA – Anaphylactic reaction due to peanuts, initial encounter
T78.01XD – Anaphylactic reaction due to peanuts, subsequent encounter
T78.01XS – Anaphylactic reaction due to peanuts, sequela
T78.02XA – Anaphylactic reaction due to other nuts and seeds, initial encounter
T78.02XD – Anaphylactic reaction due to other nuts and seeds, subsequent encounter
T78.02XS – Anaphylactic reaction due to other nuts and seeds, sequela
Z91.010 – Allergy to peanuts
Z91.018 – Allergy to other nuts
Z91.019 – Allergy to unspecified nuts

define "AllergicToDrugX":
  UCE."Active Confirmed Allergies and Intolerances" A
    where A.code ~ "DrugX"

NOTE: Content for this page was adapted from the QICore Authoring Patterns - Allergies topic.