HL7 v2.5.1 Specificationsv2.5.1

to moveEnter to openTry PID-5, ADT, 0004

AL1 segment

The AL1 segment contains patient allergy information of various types. Most of this information will be derived from user-defined tables. Each AL1 segment describes a single patient allergy.

The shape of one line

segmentAL1|AL1-1Set ID - AL1|AL1-2Allergen Type Code|AL1-3Allergen Code/Mnemonic/D…|AL1-4Allergy Severity Code|AL1-5Allergy Reaction Code|AL1-6Identification Date

required optional kept for older systems, still counted

Count the pipes to find a field, and count the empty ones too: an empty field still holds its place. Leave out the separator before AL1-3 and its value arrives as AL1-2, so the receiver stores Allergen Code/Mnemonic/Description as Allergen Type Code.

This page carries the AL1 field table as published and nothing beyond it. The field notes, vendor behaviour, FHIR mapping and parsing guidance that thePID page has are still to be written for AL1.

Every field

SEQLENDTOPTRP/#TBL#ITEM#Element nameCardinality
AL1-14SIR00203Set ID - AL11..1
250CEO012700204Allergen Type Code0..1

AL1-2 is a CE, which holds 6 components separated by carets.

SEQLENDTOPTTBL#Component name
CE.120STOIdentifier
CE.2199STOText
CE.320IDO0396Name of Coding System
CE.420STOAlternate Identifier
CE.5199STOAlternate Text
CE.620IDO0396Name of Alternate Coding System
250CER00205Allergen Code/Mnemonic/Description1..1

AL1-3 is a CE, which holds 6 components separated by carets.

SEQLENDTOPTTBL#Component name
CE.120STOIdentifier
CE.2199STOText
CE.320IDO0396Name of Coding System
CE.420STOAlternate Identifier
CE.5199STOAlternate Text
CE.620IDO0396Name of Alternate Coding System
250CEO012800206Allergy Severity Code0..1

AL1-4 is a CE, which holds 6 components separated by carets.

SEQLENDTOPTTBL#Component name
CE.120STOIdentifier
CE.2199STOText
CE.320IDO0396Name of Coding System
CE.420STOAlternate Identifier
CE.5199STOAlternate Text
CE.620IDO0396Name of Alternate Coding System
AL1-515STOY00207Allergy Reaction Code0..*
AL1-68DTB00208Identification Date deprecated0..1

Message types carrying AL1

AL1 appears in 33 message structures, belonging to 23 message types.