Welcome and introductions

2

@Peter Williams

@Rob Hausam

Recording, notes & attendance.

Summary of previous week and previous fortnight

5

@Peter Williams

@Rob Hausam

• 2020-05-26 - SNOMED on FHIR Meeting (TB)

• 2020-05-19 - SNOMED on FHIR Meeting (TS)

Other Meetings

10

@Peter Williams

Upcoming events:

FHIR Dev Days also an online event June 15 - 17.

HL7 Baltimore Sept 19 - 25. Confirmed fully virtual event. Connectathon Sept 9 - 11 (two weeks earlier)

SI Business + Expo October Lisbon. Confirmed fully virtual event. SNOMED on FHIR Presentation.

November FHIRLY Dev Days expected.

Use of system and version parameters in Lookup and Subsumes

15

@Jon Zammit

Clarification that system parameter is the "class" of the code system and so is always http://snomed.info/sct in our case. The instance of the code system ie a specific extension and effectiveTime should be supplied in the version parameter. Snowstorm and Ontoserver are aligned in this regard.. In the case of SNOMED CT we use a URI to declare our instance and so the system is entirely redundant in our specific case and the decision was made to not insist in it's use for Snowstorm.

https://temp-snowstorm.ihtsdotools.org/fhir/CodeSystem/$lookup?version=http://snomed.info/sct/900000000000207008&code=840539006

DK: FSH apparently has no way of specifying the version of a CodeSystem. Daniel checking the ANTLR spec. https://github.com/FHIR/sushi/issues/473

GPS and FHIR value set url(s)

15

@Rob Hausam

@Peter Jordan

https://chat.fhir.org/#narrow/stream/179202-terminology/topic/Indicating.20in.20a.20ValueSet.20.20SNOMED.20CT.20GPS.20.20Codes

What module(s) to use for the Canadian Edition

10

@Peter Williams

List of SNOMED CT Edition URIs replaced with 4.4.2 Edition URI Examples

TODO: Check UK Modules in 4.4.1 National Editions

Working with unversioned content

15

@Peter Williams

@Daniel Karlsson

Proposed example: http://localhost:8080/fhir/ValueSet/$expand?url=http://snomed.info/sct/45991000052106/version/UNVERSIONED?fhir_vs=isa/27624003&designation=sv

ML makes the case that unpublished content is not legitimate SNOMED and suggested using a not-SNOMED URI eg  http://snomed.info/xsct/45991000052106 in this case the code system would still be  http://snomed.info/xsct

Outstanding question: our pre-release (alpha + beta) packages do have a version as a future date in them, and continue to exist (although unpublished) even after the official release has shipped.

How would this look in a ValueSet expansion? Should we specify systemVersion or forceVersion in this case?

Update 2 June: LOINC have a similar issue with "Pre-release" identifiers - current release 2.6.7. Version 2.6.8PRE will contain the pre-release content. "To be useful they need to be considered part of the code system"

However in the case of SNOMED CT we would NOT condone unpublished identifiers being used in production systems. In the case of the COVID-19 concepts an interim release was done as an official release for 20200309. The use case here is for producers of SNOMED CT to reference concepts internally - as a work in progress.

FHIR Roadmap

5

@Peter Jordan

R5 being pushed back. GG seeking opinion on 4.1.0 - an opportunity to clean up some descriptions.

FHIR Server Federation

10

@michael lawley

Use case for fall back lookup when server does not know the answer to any particular question eg a façade server which has knowledge of all services it could potentially delegate to.

Language Reference Sets in FHIR

45

All

Mechanisms for working with Languages

Designation extension

Update 19 May: Suggestion that we work an example for SNOMED to discuss with Regenstrief (LOINC)

Update 2 June: Started worked example Designation Extension Example

SNOMED Family of Languages

10

@Peter Jordan

@michael lawley

Impact of proposed changes (eg text searching in ECL) on FHIR. Questions around which language reference sets to use when there are multiple, especially partial/overriding context (referred to MAG for discussion)

SNOMED FHIR Implementation Guide

60

@Peter Williams

Implementation Guide for using SNOMED CT with FHIR.

Update 10 Dec: DK - main problem is URI/Ls which publisher has fixed ideas about. Publisher does not examine all folders - looks in profiles but not subfolders and doesn't seem to look in ValueSet folder.

Update 21 Jan: DK and RH have merged commits and these can be seen in the HL7 server build: http://build.fhir.org/ig/IHTSDO/snomed-ig/branches/new-template/ and build errors here: http://build.fhir.org/ig/IHTSDO/snomed-ig/branches/new-template/qa.html

Update 11 Feb: Grahame said that he'd show us how to set the URI so that it doesn't have to follow the base URI. Next person to try that can we fire a Zulip off to ask about it?

Update 16 June: DK wondered about moving everything to FSH (FHIR Short Hand) as it's so much easier to maintain. ML: Conversion available, but round trip problematic. DK page Re: snowstorm FHIR requirements, issues, etc.

IG Documentation: http://build.fhir.org/ig/FHIR/ig-guidance/index.html

Also look at the sample IG https://github.com/fhir/sample-ig see build http://build.fhir.org/ig/FHIR/sample-ig/

Any other business

Next time: Continue IG

API for FHIR Resource ↔ Post coordinated expression mapping

@Peter Williams

API for FHIR Resource to SNOMED Expression

Looking up an SCTID in an unknown module

@Peter Williams

Problems when dependencies do not align. Multiple code system resources represent multiple editions / versions.

ML: See code parameter to code system search. Should return code systems (ie versions) where that code is defined. International concepts would appear in every edition known to the server.

eg /CodeSystem?system=htp://snomed.info/sct&code=12345678&_elements=version

GPS

See Discussion on Global Patient Set (GPS)

FHIR Shorthand

@michael lawley

https://github.com/HL7/fhir-shorthand/wiki

https://build.fhir.org/ig/HL7/fhir-shorthand/FSHQuickReference.pdf

Tooling: https://github.com/FHIR/sushi

$lookup operation - properties returned

@Peter Jordan

Using http://ontoserver.csiro.au/vstool/  I noticed that both Ontoserver and SnowStorm return a SNOMED CT $lookup property for effectiveTime, which I don't see listed, as one of the SNOMED CT properties in the FHIR R4 specification at http://hl7.org/fhir/snomedct.html. Should we create a Jira TIcket to add this?

Completed - https://jira.hl7.org/browse/FHIR-26555

Use of url parameter

15

@Peter Williams

CodeSystem "class vs instance" in url parameter between CodeSystem and ValueSet operations.

CodeSystem is understood.

In Valueset, url is the ValueSet url for example url = http://snomed.info/sct?fhir_vs= allows for the version URI to be used as stated in https://build.fhir.org/snomedct.html The base URL is either http://snomed.info/sct 

The ValueSet version valueSetVersion is just some string identifier eg a timestamp or 0.1.0

ECL in the Valueset Expression Extension

10

@Rob Hausam

Check whether SNOMED ECL is (or should be) registered as a MIME type (as per RFC 4289/BCP 13), or alternatively added to the expression-language code system and value set, for use in the valueset-expression extension used with the ValueSet resource.

For example, HL7 have registered application/json+fhir

This is useful for a ValueSet extension which allows any language to be used to define the selection criteria for an intensional definition using a MIME type. This group has no current reason to use that extension given the existing core specification support for implicit ValueSet definition and the support within the compose element.

RDF community may have an interest.

Update 2 June RH: Existing small valueset extended in BCP13 (existing known codes could be published as a CodeFragment). Vocab Working Group discussion ongoing.

Behaviour on Lookup

10

What properties are returned?

Discussion: Both Ontoserver and Snowstorm are returning EffectiveTime which is not listed here (unlike other SNOMED specifics): https://build.fhir.org/snomedct.html

Point of interest: Grahame's server returns a copyright property.

Update 7 April - Question about whether this is required / desirable?