Peter G. Williams

Rob Hausam

Recording, notes & attendance.

Recent events:

10:00 UTC from Wednesday 16 March 2022 every 4 weeks (the "off" week from this call). TB & TS.

Upcoming events:

April 2 -7 SNOMED International Business Meeting (London / Hybrid) 

Sunday 3 April 0800 - 11:30 UTC TB & TS

Note that the Tuesday call for 5 April has been cancelled due to having the meeting on the Sunday instead.

HL7 May 2 - 4 (running in Eastern Time) 2022 Dallas  Virtual .  9 - 13 Working Group Meetings

Peter Jordan

Rob Hausam

20

Marie-Alexandra Lambot

Implementation Guide for Use of SNOMED CT in Documentation of Allergy, Non-allergic Hypersensitivity and Intolerance" 

The SNOMED Allergy CRG have developed guidelines for representing allergies in EHRs and messages. It contains a section on the use of FHIR AllergyIntolerance resource which refers to the two SNOMED on FHIR AllergyIntolerence profiles.

The current (R4, and future R5) FHIR resource does not have sufficient detail to allow mapping to the SNOMED allergy model. Could be raised by the HL7 Patient Care WG.

8 Feb 2022 - MAL reported meeting DK and he's put some of the examples (see here) in the document into JSON.  Other minor corrections.   

2022-02-22: AllergyIntolerance detailedType extension, check allowed cardinality is 0..1.

http://build.fhir.org/ig/IHTSDO/snomed-ig/branches/allergy_guide/StructureDefinition-allergy-intolerance-detailed-type.html

2022-03-08 Looking for Rob Hausamreview prior to business meeting (presentation expected at Clinical Leads (Jane's group)

Kai Kewley

2022-02-22:  Presentation: https://docs.google.com/presentation/d/1Kz-8N6UQsGZ8C1xsC8TZT6LEbeyr6elrgMt2FI-whjU

• Supplements might not be able to hold new concepts: https://www.hl7.org/fhir/codesystem.html#supplements bullet no 4.
  • (Ontoserver seems to do this: https://ontoserver.csiro.au/docs/6/postcoordination.html#Expression_Libraries )

Proposal might include using side-effects which some might be sensitive to.

Runtime maintenance is required. Is it possible to reuse the existing API in order to standardize the approach?

A Code System Supplement may be used to hold a set of postcoordinated expressions as FHIR concepts

• This approach used by Ontoserver so that they are "known" to the Terminology Server so that $expand can be used without considering all possible PCEs.  Not that some clients may not be able to process PCEs so the CS Supplement allows these to be kept separate.  Michael Lawley will raise ticket to "Add parameter to ValueSet $expand to specify Code System Supplements to be included" (would need to be compatible with code system that the ValueSet is being expanded against)
• "No requirement for a designation"

CodeSystem/$validate-code operation could be used to validate the expression

• Yes (doesn't need previous knowledge of the PCE, similarly for $lookup

Could calling CodeSystem/$lookup automatically create expression concepts in the supplement, to be returned in ECL queries for analytics? Or use PATCH?

• Probably not, see use of Supplement above.   Yes use of PATCH seems reasonable (PUT a whole new version more common, but PATCH might allow for finer grained updates ie not having to re-submit the entire cohort of expressions).   ML: Custom operation might be useful here to add to the codeSystem and update the ConceptMap in one go.

ConceptMap/$translate could translate an expression to a single identifier to support more limited clinical record systems.  Could this work in real time, automatically creating entries as required?

• ML: Use a local CodeSystem for the expression identifiers and a concept map to link them together.

Rob Hausam

Discussion about proposed federation.  ML Doesn't work so well with SNOMED CT because there's not a single authoritative source due to country extensions (and multiple versions being released).  Use case for this is mainly in creation of IGs.  Agreement that what a conformant server should be able to state in Capability Statement is helpful.   ML Touchstone test script artefacts need investment.  See https://touchstone.aegis.net/touchstone/

See also https://inferno.healthit.gov/

16 Nov Update RH: Updates in for next ballot (not January now).

8 Feb RH: Next ballot confirmed May (deadline March 6, since extended 2 - 3 months)

8 March RH Community being polled on preferred approach to next release from three options: 1. R5 Release with additional Normative content (ie in 2023) 2. Hold R5 3. New content, but not new normative content (looking most popular option).   See https://onfhir.hl7.org/2022/02/28/soliciting-feedback-concerning-the-roadmap-for-fhir-r5/

Peter Jordan

Ontoserver examples: https://r4.ontoserver.csiro.au/fhir/ValueSet?_format=json

Implicit: https://r4.ontoserver.csiro.au/fhir/ValueSet/$expand?url=http://snomed.info/sct?fhir_vs=isa/410607006&count=5&_format=json

Gives url = "http://snomed.info/sct/32506021000036107/version/20211130?fhir_vs=isa%2F410607006"

Snowstorm examples: https://snowstorm.ihtsdotools.org/fhir/ValueSet

Implicit example: https://snowstorm.ihtsdotools.org/fhir/ValueSet/$expand?url=http://snomed.info/sct?fhir_vs=isa/410607006&system-version=http://snomed.info/xsct&count=5   here we just return the url parameter that was specified in the GET request.

SNOMED International follows published URI spec in this matter, see 2.6 URIs for Modelling Resources  for pre-defined ValueSets. Hmm, we agreed that valueSet was a thing that existed independently of it's implementation (Kuala Lumpur discussion) but that hasn't made it to the spec.

• Peter G. Williamsfollow up with Linda Bird

Query is about what version gets used in the parameter field.   The spec says "The server decides which parameters to include here, but at a minimum, the list SHOULD include all of the parameters that affect the $expand operation. If the expansion will be persisted all of these parameters SHALL be included. If the codeSystem on the server has a specified version then this version SHALL be provided as a parameter in the expansion (note that not all code systems have a version)."

Peter Jordan

Normally when a filter is applied eg "Size 12" + "green" we expect both qualities to be true at the same time and this is held true by the FHIR Spec that says "If multiple filters are specified, they SHALL all be true."  (see http://build.fhir.org/valueset-definitions.html#ValueSet.compose.include.filter)  However  http://hl7.org/fhir/R4/valueset-substance-code.json.html  has two filters that pick up substances PLUS products   and obviously they can't both be true at the same time.    So it seems like sometimes we use conjunction and sometimes disjunction?  

Snowstorm GitHub issue #285 changes behaviour from AND to OR when multiple filters are applied.

Answer is: the separate includes are disjunctive and objects within the same filter array are conjunctive.

Text here is clearer: http://build.fhir.org/valueset.html#compositions

SideNote:   Wildcard for versions in $expand, see https://jira.hl7.org/browse/FHIR-15998   Note that "version" here would mean multiple editions.

• Peter G. Williamsraise tracker to improve clarity of text   Done, see https://jira.hl7.org/browse/FHIR-36218

8 March - Additional comments added to ticket.

Request that SI make the GPS ValueSet available as an extensional definition.

SI are (I think - PWI) in agreement to do this.

• Peter G. Williamsticket and progress.   MAINT-1740 Target October 15 into production (need SearchAfter functionality for Refset Members).   Also check date for next GPS publication.

16 Nov Update:   "Search After" functionality will be available in Prod 1 Dec.

Daniel Karlsson

Jeremy Rogers

Collecting topics for TB stream here, with a view to having a call when there's sufficient material

FamilyMemberHistory - how is "no family history of X" best represented?

FreshDesk ticket question on Allergy substance cross field validation.  DK: Mappings to other information models, is that helpful?

Oct 5 2021 Request for input from nutrition CRG.

8 Feb 2022 MAL Patient Care group proposing the use of an extension (specified by Daniel) to represent Allergy Type to add non-allergic hypersensitivity.  MAL wondered about allowing a Codeable Concept there rather than a Code to allow for greater expressivity.   Resource not planning on being Norminative in R5.

Michael Lawley

Licensing issues for IGs referring to SNOMED codes. Is this written down anywhere with some sort of rigour?

Consider the licence statement that is presented when accessing the browser. Should something similar be mandated for inclusion in any document published? What if a patient's medical record were to be published?

• Peter G. Williams find clarity here - email discussion started with Suzy Royand Jane Millar

Update 12 Jan - "One Page Policy" to be discussed internally.   HL7 agreement indicates other parties would require affiliate licence unless they restricted their usage to the Global Patient Set.

26 Jan Question from PJ about inclusion of COVID Vaccine concepts in the GPS (advised that it is only released yearly)  FYI Rory Davidson See also MF discussion here.  SuzyR will follow up.  See also early preview page.

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

Update 17 Nov:  Proposal to add more values into designation use https://jira.hl7.org/browse/UP-107

Update 1 Dec: Latest build: http://build.fhir.org/ig/IHTSDO/snomed-ig/branches/duc/StructureDefinition-designation-use-context.html   Ticket: https://jira.hl7.org/browse/UP-155 being replaced by https://jira.hl7.org/browse/FHIR-29821   ML suggested we need an additional value for 'Not Acceptable' that would need an additional value to be explicit, rather than relying on the absence of a 'row'.   Designation Use codeset, or the infrastructure codesystem?  See also http://build.fhir.org/languages.html##term

Update 15 Dec:  Discussing cardinality - when a designation can be applied to multiple roles, do we have repeated elements in a single extension block, or multiple extension blocks?  PJ Checking use case.    Use Case:  To allow tell the client what all use contexts (roles) are available so that it can a) select one making an informed choice and b) gradual degradation where the best available terms are used where they exist, falling back to a less preferable term where they do not.  Worked example from ML: https://gist.github.com/pgwilliams/8c742d68878b1fda0638a798668e42f2    also http://build.fhir.org/ig/IHTSDO/snomed-ig/branches/lawley-patch-1/CodeSystem-CodeSystemDesignationUseExample1.html 
On question if this should be part of core spec or remain in SNOMED IG we can consider if this is of use to any other Terminology eg LOINC or RxNorm.

12 Jan Update: Rob Hausam looking for clarity to take forward with Vocab group.   How to align this with other in-flight trackers (eg https://jira.hl7.org/browse/UP-107) that propose expanding designation use which - we think - seeks to overload designation use in a way that wouldn't ( ?) allow more than one value at the same time and these features of designations can vary independently.

12 Jan Proposal:   All 3 elements (including designation type) should be included in our proposed extension.   SNOMED implementations would then pick the most appropriate designation.use value from whatever set is offered in the spec   eg FSN where it is an FSN (because - although also considered 'preferred' - these are seldom used for user interfaces), PreferredForLanguage where we have the preferred term for a given language/dialect and Synonym for anything else.

26 Jan: RH update - is ongoing discussion.  Attempting "best of both worlds" approach.  Not on the Vocab group's agenda, won't be in R4B.    Question from ML about display vs preferredForLanguage here.  Proposed extension to list of designation use will necessitate repetition of designations where they have multiple uses.   See DK example here:  http://build.fhir.org/ig/IHTSDO/snomed-ig/branches/duc/ValueSet-DrugValueSetExample1.json.html

RH: Suggestion that Ontoserver and/or Snowstorm could try an implementation of our extension.   Clients are expected to ignore extensions that they don't understand.

9 Feb 2021 ML Experience with NL and LOINC.  Could we explore using Language tag with a private X language (eg nl-x-sctlang-87587989-78574801 BCP 47: privateuse = "x" 1*("-" (1*8alphanum)) ) and the language reference set id - ie allows for things like Patient Friendly Terms.   The preferred term would be mapped to the display element.   Language tags allows for weighted preferences (ie fall back options).  Pros:  avoids an extension and re-uses an existing part of the specification.  DK "No reason not to implement this, the two approaches are not in conflict".   Question: is "Preferred for Language" definitely happening?   RH: Yes

23 Feb 2021 RH brought up discussion with Vocab group.  Check in on tracker UP-107. DK Still a requirement to present results (eg expansion) with the language refsets visible (to know which designation was in which langrefset) - better to use extension or overload core spec?   Querying is fine, issue is making clear what is being returned. Suggested possible to use the BCP47 refset form in the language element.   Difficulty when returning fall back options as display term is that we can't say what we fell back to.

9 March 2021 DK An implementation is now needed.   DK tried out with Snowstorm:  BCP-47 works but not for extension language referencesets (also for designation)  ( note dialect alias configured in application.properties is a separate solution which could also be improved: https://github.com/IHTSDO/snowstorm/blob/master/src/main/resources/application.properties#L217 ).  SM NL BCP-47solution getting great feedback.

23 March 2021 DK Testing Snowstorm which looks at designation and language headers.   Just needs attention especially for extension content.  

20 April 2021 RH Looking to target next ballot round.   Could we host this extension ourselves in the meantime and target May connectathon? Peter G. Williams

27 July RH & ML:- Still a work in progress. DK will return Aug 1; we should follow up with him next time.

ML:- Potentially fall into R5 on Ontoserver.

24 August DK Added pull request to Snowstorm  here

Implementation by ML using existing fields and specifying LangRefset in displayLanguage parameter with "preferredForLanguage" code and wildcard  Eg https://r4.ontoserver.csiro.au/fhir/ValueSet/$expand?displayLanguage=*-x-sctlang-20581000-087109&_format=json&url=http://snomed.info/sct/20611000087101?fhir_vs=ecl/160303001&includeDesignations=true

Oct 5 Release of Ontoserver 6.5.0 which includes support for language reference sets as above.

• Peter G. Williamsdocument examples using live Snowstorm instance

Next Steps:   How to promote - could we present at a Vocab call?   (1530 ET Thursdays - may clash with SI Languages call)

8 Feb 2022 DK  added Designation Extension into the SNOMED on FHIR IG see http://build.fhir.org/ig/IHTSDO/snomed-ig/StructureDefinition-designation-use-context.html

Peter G. Williams

Implementation Guide for using SNOMED CT with FHIR.

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/

• Rob Hausam to speak to Lloyd about extending the base template as per http://build.fhir.org/ig/FHIR/ig-guidance/template.html Update 24 March: Documentation on this is "TODO"
• Peter G. Williams FHIR core content to be copied over to Snowstorm instance.

TODOS 

• Check build issues http://build.fhir.org/ig/IHTSDO/snomed-ig/qa.html
• Rerun with latest tooling (also sushi)
• Run with local snowstorm provided as Tx
• See Mark Kramer presentation 
• CONTENT!  (PWI speak to PTB)
• Merge in DUC branch (Designation Use Context) with a view to implementing in a branch of Snowstorm and making available via connectathon.ihtsdotools.org
• Clean up other branches
• Check templates are up to date - should now be self updating, see https://github.com/FHIR/sample-ig (fsh may ask to update this structure).   Sushi sending out information about new format (PJ says leading whitespace is now significant).
• ReadMe should provide links for Publisher tooling
• Add discussion on Refset / IN (see above)
• Provide link to it in http://build.fhir.org/snomedct.html and discuss further socializing.
• TerminologyCapabilities caching is overly aggressive.

Discussion on * version wildcard. (relates to a Zulip discussion on expanding a ValueSet against multiple editions to give a superset?)  DK How could we specify the latest version of multiple modules.   Answer http://snomed.info/sct/*   (ie not specifying the version) or http://snomed.info/sct/*/version/*  to include concepts from previous versions.

For use in the module / version URI.   Existing workaround is to use multiple include elements for each version.

7 Sept ML Sticking point - what do we do with incompatible properties eg active/inactive between two different versions - the most recent?

Use case: primarily being able to validate codes that might exist in different editions.   Secondarily, being able to validate code received in a historical record ie where codes were valid at time of data entry.

25 Jan 2022: Snowstorm will already look across all Editions loaded when a codesystem version is not specified, eg:  https://browser.ihtsdotools.org/fhir/CodeSystem/$validate-code?coding=http://snomed.info/sct|443971000124108 only exists in the US Edition.

(See also the History proposals for ECL)

• Peter G. Williamsdocument Snowstorm multi-edition validation in IG

Rob Hausam (primarily Vocab WG)

Quick Questions:   Which International Monthly release should an extension base itself from.  Answer: that would be something for the country to decide.

Six monthly releases will (at a technical level) have no special significance.   Deltas are no longer being generated (as we can't know when the last 'consumed' point would be) but can be created on demand using  https://github.com/IHTSDO/delta-generator-tool

Question for Nick Egarhosout of curiosity are there any vendors out there who implement just the International Edition in their software?  Do we have vendors using some country extension in other unrelated countries?

Peter G. Williams: There are definitely vendors that only implement the International Edition depending on the type of application (i.e. fairly generic content) and geographic extent of their market.  There are very few examples of vendors using a country's extension in another country, one that comes to mind was Saudi Arabia's interest in using Australian codes.

Next time:   

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)

8 Sept The FHIR specification does not specify a particular version of ECL, so we assume the latest.  Any enhancements added to ECL will be immediately relevant and available in FHIR.   Note that these latest additions while targeting descriptions are a concept filter, so display options (language etc) will affect the output of those concepts.   How about the filter parameter though, especially since ECL would allow multiple filters in multiple/different languages.

• Michael Lawley Suggested ticket: Parent and Child properties to (optionally?) support the Coding type.

Daniel Karlsson

Peter G. Williams

API for FHIR Resource to SNOMED Expression

• Daniel Karlsson Thought there might be some documentation from CIMI on this. Also notes from DMarkwell about constructor bindings.
• Peter G. Williams Pull these notes into confluence - can we mention it in the IG?

Peter G. 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

• Peter G. Williams Ticket implementing this lookup. Note that this could be implemented more generally for lookups of http://snomed.info/id/<SCTID> where the SCTID exists in an extension. Done - see STORM-262.

Peter G. 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 , or the URI for the edition version, in the format specified by SNOMED International in the SNOMED CT URI Specification.

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

Rob Hausam

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

• Peter Jordan to raise a Jira ticket to ask for this to be returned - completed https://jira.hl7.org/browse/FHIR-26555

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

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

Michael Lawley

Terminology Capabilities: Default SNOMED Edition for a Server. Suggestion to invite Graham for a wider discussion. Resource is still at maturity 0.

11 August The resource is based on instances of code systems. Difficult to make statements about code systems generally, or specific SNOMED editions, etc. Will start a Zulip discussion on this. Michael Lawley Then potentially invite Grahame for a future discussion?

25 August It has been agreed that this resource will now have maturity level 1

See https://chat.fhir.org/#narrow/stream/179202-terminology/topic/tx.2Efhir.2Eorg.20New.20parameters.20for.20.24expand.20.26.20.24validate-code

8 Sept 20 Is there a Jira ticket ?   Rob says Grahame implemented this.

12 Jan:  RH update made to GG Server.   Documentation (assuming required) still outstanding.

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.

Aug 25: New capabilities in HAPI to allow delegation to an external terminology server.