> For the complete documentation index, see [llms.txt](https://docs.snomed.org/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.snomed.org/implementation-guides/allergy-implementation-guide/appendixes/appendix-d-analysis-of-the-hl7-patient-care-domain-analysis-model.md). # Appendix D: Analysis of the HL7 Patient Care Domain Analysis Model This domain analysis model for allergy records was developed by the HL7 Patient Care Work Group and has been used to inform the allergy/intolerance modeling in the C-CDA® and FHIR® specifications. Patient Care Domain Analysis Model

**Selected attribute definitions**

Attribute name	Datatype	Definition
Adverse reaction
severity	Coded	Assessment of the severity of the reaction
didNotOccurFlag	Boolean	Indicates a reaction did not occur at contact with substance
OccurrenceDate	DateTime	Time stamp for manifestation of the reaction
Health condition
status	Coded	Current status of the concern
Adverse sensitivity to substance
criticality	Coded	Clinical judgement regarding potential seriousness of a future reaction.
sensitivityType	Coded	Allergy; intolerance
createdDate	Date Time	Date time the entry was created
Substance
identifier	Coded	Coded reference to the substance involved in the reaction
name	String	Name of the substance
Exposure
exposureDate	Date Time	Date time when the exposure occurred; may be approximated
exposureType	Coded	How the exposure occurred, eg vaccination, prescription, administration, accidental
Manifestation
severity	Coded	Severity of the manifestation of the reaction
reactionType	Coded	Clinical finding characterizing the reaction, eg code for rash or hives
Sensitivity test
identifier	Identifier	Identifier pointing to results of the sensitivity test
name	String	Name of the test

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