HL7 Version 2 to FHIR
1.0.0 - STU 1

HL7 Version 2 to FHIR - Downloaded Version 1.0.0 See the Directory of published versions

## ConceptMap: Segment AL1 to AllergyIntolerance Map (Experimental)

Official URL: http://hl7.org/fhir/uv/v2mappings/ConceptMap/segment-al1-to-allergyintolerance | Version: 1.0.0
Standards status: Informative | Computable Name: SegmentAL1ToAllergyIntolerance
Copyright/Legal: Copyright (c) 2025, HL7 International, Inc., All Rights Reserved.

This ConceptMap represents a mapping from the HL7 V2 Segment AL1 to the FHIR AllergyIntolerance Resource.

This ConceptMap represents the mapping from the HL7 V2 AL1 Segment to the FHIR AllergyIntolerance Resource. See also the FHIR Shorthand or the CSV Source.

HL7 v2 | Condition (IF True, args) | HL7 FHIR | Comments
--- | --- | --- | ---
Sort Order | Identifier | Name | Data Type | Cardinality - Min | Cardinality - Max | Computable ANTLR | Computable FHIRPath | Narrative | FHIR Attribute | Extension | Data Type | Cardinality - Min | Cardinality - Max | Data Type Mapping | Vocabulary Mapping (IS, ID, CE, CEN, CWE) | Assignment
0 | AL1 |  |  |  |  |  |  |  | AllergyIntolerance.clinicalStatus.coding.code |  | code | 0 | 1 |  |  | "active" | While .clinicalStatus is not required, constraint ait-1 (AllergyIntolerance.clinicalStatus SHALL be present if verificationStatus is not entered-in-error.) does necessitate populating this element in the map as it's not possible to infer a verificationStatus of "entered-in-error" based on the data in AL1.
0 | AL1 |  |  |  |  |  |  |  | AllergyIntolerance.clinicalStatus.coding.system |  | uri | 0 | 1 |  |  | "http://terminology.hl7.org/CodeSystem/allergyintolerance-clinical" |
1 | AL1-1 | Set ID - AL1 | SI | 1 | 1 |  |  |  |  |  |  |  |  |  |  |  | This field doesn't warrant mapping
2 | AL1-2 | Allergen Type Code | CWE | 0 | 1 |  |  |  | AllergyIntolerance.category |  | code | 0 | -1 | CWE[code] | AllergenType[AllergyIntoleranceCategory] |  | The FHIR table has a "required" binding. Do we need to expand the values in the FHIR table? Could other be used for: Miscellaneous allergy Miscellaneous contraindication Animal Allergy HL70127 is a user defined table
2 | AL1-2 | Allergen Type Code | CWE | 0 | 1 |  |  |  | AllergyIntolerance.category.extension.url |  | uri | 1 | 1 |  |  | "http://hl7.org/fhir/StructureDefinition/alternate-codes" |
2 | AL1-2 | Allergen Type Code | CWE | 0 | 1 |  |  |  | AllergyIntolerance.category.extension.valueCodeableConcept |  | CodeableConcept | 1 | 1 | CWE[CodeableConcept] | AllergenType[AllergyIntoleranceOriginalCategory] |  |
2 | AL1-2 | Allergen Type Code | CWE | 0 | 1 |  |  |  | AllergyIntolerance.type |  | code | 0 | 1 | CWE[code] | AllergyType |  |
3 | AL1-3 | Allergen Code/Mnemonic/Description | CWE | 1 | 1 |  |  |  | code |  | CodeableConcept | 0 | 1 | CWE[CodeableConcept] |  |  |
4 | AL1-4 | Allergy Severity Code | CWE | 0 | 1 |  |  | If severity was used equivalent to criticality | AllergyIntolerance.criticality |  | code | 0 | 1 | CWE[code] | AllergySeverity[AllergyIntolerance.criticality] |  | Note that AllergyIntolerance.reaction.severity is available in FHIR but from a base standard perspective that is actually not the most appropriate and would require that AL1-6 is valued as well. However, a local implementation may have used vocabulary that better fits AllergyIntolerance.reaction.severity and should then consider that instead as a local variation. Note that the .reaction though is at a particular time, while .criticality is an overall assement that matches HL7 v2 generally better.
4 | AL1-4 | Allergy Severity Code | CWE | 0 | 1 |  |  | If severity was used equivalent to criticality | AllergyIntolerance.criticality.extension.url |  | uri | 1 | 1 |  |  | "http://hl7.org/fhir/StructureDefinition/alternate-codes" |
4 | AL1-4 | Allergy Severity Code | CWE | 0 | 1 |  |  | If severity was used equivalent to criticality | AllergyIntolerance.criticality.extension.valueCodeableConcept |  | CodeableConcept | 1 | 1 | CWE[CodeableConcept] | AllergySeverity[AllergyIntolerance.criticality-original] |  |
4 | AL1-4 | Allergy Severity Code | CWE | 0 | 1 |  |  | If severity was not used equivalent to criticality | AllergyIntolerance.reaction.severity |  | code | 0 | 1 | CWE[Code] | AllergySeverity[AllergyIntolerance.reaction.severity] |  |
5 | AL1-5 | Allergy Reaction Code | ST | 0 | -1 |  |  |  | AllergyIntolerance.reaction.manifestation.text |  | CodeableConcept | 0 | 1 | ST[CodeableConcept] |  |  | AllergyIntolerance.reaction can repeat, presumably to capture both multiple manifestations of the reaction (rash and nausea) as well as reactions to independent exposures (last week and last month) - we may want to confirm this understanding.
6 | AL1-6 | Identification Date | DT | 1 | 1 |  |  |  | AllergyIntolerance.onsetDateTime |  | dateTime | 0 | 1 |  |  |  | Withdrawn as of 2.7, Refer to IAM-11 Onset or IAM-13 Reported Date

Mapping from (not specified) to (not specified)

Group 1 Mapping from `unspecified code system` to `unspecified code system`

Source Concept Details | Relationship | Target Concept Details | Comment
Codes from | NarrativeCondition |  | Codes from |
AL1 |  |  | is equivalent to | clinicalStatus.coding.code | clinicalStatus.coding.code | While .clinicalStatus is not required, constraint ait-1 (AllergyIntolerance.clinicalStatus SHALL be present if verificationStatus is not entered-in-error.) does necessitate populating this element in the map as it's not possible to infer a verificationStatus of "entered-in-error" based on the data in AL1.
AL1 |  |  | is equivalent to | clinicalStatus.coding.system | clinicalStatus.coding.system |
AL1-2 | Allergen Type Code |  | is equivalent to | category | category | The FHIR table has a "required" binding. Do we need to expand the values in the FHIR table? Could other be used for: Miscellaneous allergy Miscellaneous contraindication Animal Allergy HL70127 is a user defined table\
AL1-2 | Allergen Type Code |  | is equivalent to | category.extension[1].url | category.extension[1].url |
AL1-2 | Allergen Type Code |  | is equivalent to | category.extension[1].valueCodeableConcept | category.extension[1].valueCodeableConcept |
AL1-2 | Allergen Type Code |  | is equivalent to | type | type |
AL1-3 | Allergen Code/Mnemonic/Description |  | is equivalent to | code | code |
AL1-4 | Allergy Severity Code | If severity was used equivalent to criticality | is equivalent to | criticality | criticality | Note that AllergyIntolerance.reaction.severity is available in FHIR but from a base standard perspective that is actually not the most appropriate and would require that AL1-6 is valued as well. However, a local implementation may have used vocabulary that better fits AllergyIntolerance.reaction.severity and should then consider that instead as a local variation. Note that the .reaction though is at a particular time, while .criticality is an overall assement that matches HL7 v2 generally better.
AL1-4 | Allergy Severity Code | If severity was used equivalent to criticality | is equivalent to | criticality.extension[1].url | criticality.extension[1].url |
AL1-4 | Allergy Severity Code | If severity was used equivalent to criticality | is equivalent to | criticality.extension[1].valueCodeableConcept | criticality.extension[1].valueCodeableConcept |
AL1-4 | Allergy Severity Code | If severity was not used equivalent to criticality | is equivalent to | reaction.severity | reaction.severity |
AL1-5 | Allergy Reaction Code |  | is equivalent to | reaction.manifestation.text | reaction.manifestation.text | AllergyIntolerance.reaction can repeat, presumably to capture both multiple manifestations of the reaction (rash and nausea) as well as reactions to independent exposures (last week and last month) - we may want to confirm this understanding.\
AL1-6 | Identification Date |  | is equivalent to | onsetDateTime | onsetDateTime | Withdrawn as of 2.7, Refer to IAM-11 Onset or IAM-13 Reported Date

### Notes: