HL7AU - FHIR WG : 2023-04-26 Minutes

Web Conference details:

11am Sydney time

PC, Mac, Linux, iOS or Android: https://zoom.us/j/7479215691

or Phone: +61 (0) 2 8015 2088, Meeting ID: 747 921 5691

Attendees

Agenda

• R5 Sex Gender Harmony (see pre-adopt R5 sex and gender harmony build) - any progress?
• HL7 AU CodeSystem.valueSet approach
• R5 reconciliation
• Pull requests:
  
  • Add FMM to HL7 AU Terminology (see PR #783 build)
  • Add ElementDefinition.condition in StructureDefinitions (see PR # 784 build)

Background to HL7 AU CodeSystem.valueSet approach (Issue #785)

HL7 AU code systems published in AU Base are missing CodeSystem.valueSet property (already present in AU PD).

As good practice CodeSystem resources should define the "all codes value set in the code system ValueSet" (i.e CodeSystem.valueSet). If that attribute is set, then a terminology server does not need an explicit ValueSet in order to be able to expand it. This is because the definition is implied. Hence, all that is needed is the CodeSystem itself.

Early discussions around the 'all codes' value set for an HL7 AU code system definition (implemented in AU PD) were that:

1. The 'all codes' value set is to be defined with the same values as the CodeSystem except for url, i.e. should share same name, id, title but the terminology namespace is different.
   1.This value is used in CodeSystem.valueSet.
2. If an explicit 'effective all codes' value set is required (e.g. 'active' codes or something other definition of effective) it shall have a different name and id to the CodeSystem (and therefore different URL to the 'all codes' value set)
3. There may or may not be a published and maintained ValueSet resource for the 'all codes' value set

The above convention is

• implemented in AU PD, and in most HL7 FHIR terminologies that support an 'all codes' value set in CodeSystem.valueSet.
• SNOMED defines an 'all codes' value set in using 'fhir_vs' i.e. 'http://snomed.info/sct/fhir_vs'.
• LOINC and NCTS support only implicit value sets in CodeSystem.valueSet by using the convention '<code system URL/vs>' e.g. https://healthterminologies.gov.au/fhir/CodeSystem/australian-benefit-payment-category-1/vs

Issue with implementing above convention
The existing convention works well for everything except Contact Purpose, the 'all codes' value set URL is already in use for a value set that includes concepts from two code systems (bound in StructureDefinitions). I don’t think changing the url of the bound value set is feasible as it has gone through two rounds of ballot and is implemented in at least PCA, and is present in other ‘final’ implementation guides even if the products may not use it.

For discussion in HL7 AU FHIR working group

1. Convention to adopt in HL7 AU CodeSystem.valueSet:
   1. use 'all codes' value set URL (decide how to deal with Contact Purpose as an exception)
   2. use a value that is always implicit and can never match an explicit ValueSet e.g. <CodeSystem.url/vs>
   3. something else?

For reference, current working branch is here: GitHub | Build.fhir.org

Minutes

1) no new info; branch updated with individual pronouns; recorded sex and gender as above

• RD: sex parameter for clinical use; would be good to complete ballot reconciliation before merging - FHIRWG this will not  be merged
• recorded sex or gender and individual pronouns will be merged into the main trunk from the branch for visibility and trial use

2) Discussed  CodeSystem.valueset - valueset naming like following; the valuset returned will have Valueset.url set to to this

Suggested pattern: http://terminology.hl7.org.au/ValueSet/<id> - FHIRWG agree

• DTR/BE put a proposal together re review of profiles of AU Core to get to FMM 1 commitee reviewed 
• Consent to contact: HF/AB
• AM: Observation resource as a pathology panel