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Date 20:00 UTC on Tuesday 1 June 2021 - 90 minutes.   


  • FHIR Terminology Services and Resources

Discussion items



OwnerNotes & Actions
1Welcome and introductions2

Recording, notes & attendance.

2Previous Meetings5

2021-05-11 - SNOMED on FHIR Meeting (TB)

3Other Meetings5

Recent events:

FHIR Working Group May 24 - 28 will be UTC time based. SR: if RH can get more details for the events, SI may be able to help out. PJ: are there any fhir tools that we can use/show R5.  Update 1 June ConceptMap discussion (R5 changes) posted by Carmilla.

Upcoming events:

FHIR Dev Days by Fhirly June 7 - 10 (Virtual US time based)  March 1 deadline for presentation proposals.  RH has one proposal accepted, CSIRO also presenting.  PWI repeating Intro to SNOMED with FHIR.   Previous Introduction to FHIR presentation (Follow the Yellow Brick Code): _

SI October Expo  (Fully Virtual) 

4IPS Descriptions15Peter Jordan

IPS IG - Discussion on which description to pass, which may be specific to particular editions.   Should FSN be passed then as the most commonly used identifier?    What do you do with a known Concept ID where the description text is not recognised ie from some other extension.  ML - understanding the context of use is important when deciding what error message should be retrieved and may inform whether or not to pass the text as part of the validation. DK - A shared code system should be agreed between two entities that are transferring data with an agreed translation (with English being available for a fall back if no other common language available).  ML - note that the displayLanguage parameter can be used as an input to $validate-code to inform the server about what the term to be validated is.  PWI - Snowstorm API currently allows for description (and concept) lookup across all published modules / versions.  This functionality could be used to consider a concept and a description being separately published in different extensions.   ML - The full version URI of the concept could be used to indicate the module & version being used - even if the concept being referenced came from some dependency.   Also the mismatch response could be specific about the CodeSystemVersion being used in the validation.  Making validation calls without + with the description still an option and question of what to do about validation failure still down to the client.

Archive Next Time

5Post Coordination with SLPG30Linda Bird

Proposed topics for this week's 'SNOMED on FHIR' meeting (as a joint SLPG-FHIR topic)

    • What is the functionality scope of a terminology server that supports postcoordination? For example, does it include:
      • Classifying multiple expressions in a single substrate? What are the use cases for this?
      • Assigning (local) identifiers to expressions? What are the use cases for this?
      • Autogenerating or assigning a term to an expression? What are the use cases for this? SM: See GitHub Issue.
    • Does a terminology server that supports postcoordination, include all the functions of an expression repository?
    • What is the relationship between a terminology server that supports postcoordination, and an expression repository?

ML: Role of an expression repository.  Expressions are public things.  Local identifiers are a workaround and should never be seen outside of the EMR (and possibly even by a TS).   Classifying multiple expression together might happen in the context of a CodeSystemSupplement or in a $closure operation.   Terms may be generate eg for $lookup.  Ontoserver generates term closely following attributes after some normalization.  "In the case of multiple expressions eg as intermediate parents we would need to look up the hierarchy until a pre-coordinated concept is found to use as the focus concept".   

Discussion of whether arbitrary nesting could be used for expression to return PostCE as focus concept eg   (X:Y=Z):A=B   (LB says not, although something similar is viable in ECL, see SCG spec).  Broader question on functionality in Expression Repositories particularly on identifiers (used for caching and due to lack of space in records). SM: Vendors have fear of PCEs and prefer identifiers. ML Focus concept could be the focus concept of the underlying expression [PWI and shift the refinements to the right of the colon? ] ML NB NNF of an expression only exists for FHIR - it's not part of the SNOMED spec.  NNF's use case may be questionable.

6PCE implications for FHIR Operations

$validate-code, obviously.   ML  Transformations of Close to User Form happen under the hood of the TS.   You might want to see normalized form, although it will be dependent on the particular edition in use.    Current Snowstorm development is WIP / experimental rather than a ratified spec.   Order of transformation is important + existing issues with negation in hierarchy subsuming in unwanted ways.   PJ Essential to have first pass attempt to bottom out issues, highly beneficial. 


What about ValueSet $expand - return Normalized form or original input?   Classification will be needed before membership of ValueSets can be determined.

$find-matches could be used to find / check PCEs / Normalized equivalencies.   Alternatively, deprecate this operation altogether!

$translate could return normalized forms of CTUF.  ML Syntactic differentiator needed?

7Topics for Terminology Binding Stream

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?

15 Dec 2020 DK Asking if the member forum are still keen to see engagement in this area - offer to help country implementations.   Difficult to make decisions on binding without a concrete use case.  ML We could look at / review IGs (DK As we did for COVID).

  • Suzy Royplease work with Daniel and Nick E. to take forward something appropriate for next MF (will be in the New Year).

12 Jan 2021 Update: Contact planned with the MF - next call (Jan 22) is topic based, so after that one - 2 Feb (with Daniel)

9 Feb 2021 Update: Briefing note (DK) ready to be presented to MF.   Now (23 Feb) submitted for discussion, waiting for date in March or April.

9 March 2021 Update: Daniel to present to MF on 11 March (Thursday!)

23 March Update:  Presentation given, awaiting feedback.   Reminder Suzy Roy?

06 April Update: SR There's a follow up in April business meeting (member forum meeting) for feedback. DK reading through/presenting resources may not have been the best approach; maybe presenting use cases would be better. PJ agrees as its more relatable. 

20 April:   Topic for discussion - new Resources introduced in R4B.    Also (Linn Brandt) Use case: Registries need nullFlavor-concepts in their value sets. Which code system to use?  Consider "Long COVID no longer present" as a topical example.  4 May DK: This is more of a negation issue than null flavour, also probability.   JL Distinction between unknown and uncertain.

4 May Jay Lyle - FHIR Binding, proposal review in Observations and presence of findings eg for more of an examination based context. 

1 June Peter G. Williams to check in with JL.

8R5 Position2

ML ConceptMap moving from R4 to R5.

9 March 2021: Last updates coming in, delayed due to tooling issues.   Balloting open in next few days.

06 April 2021: RH R4B went to ballot couple weeks ago.   "R4B planned for late Q2 or sometime in Q3, 2021"

20 April 2021 : R5 Balloting has commenced (using Jira for the first time) until May 17. 

1 June Next Ballot Jan 2022

9Publishing SNOMED codes in IGs and licencing conditions.

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 somethig similar be mandated for inclusion in any document published? What if a patient's medical record were to be published?

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.

06 April: SR covid vaccines have been/will be incorporated into July release. They will be in GPS when ready. 

10Working with unversioned content15

Page to go through further discussion:  URI Proposal: Addition of xsct

11Language Reference Sets in FHIR45All

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

Update 1 Dec: Latest build:   Ticket: being replaced by   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

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    also 
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 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:

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 is a separate solution which could also be improved: ).  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

12SNOMED FHIR Implementation Guide60

Implementation Guide for using SNOMED CT with FHIR.

IG Documentation:

Also look at the sample IG see build


Any other business

Next time:      (Philip Chuang) Note conflict with the filter "Reference Set" causes confusion with the "In" operator being a list of codes in other CodeSystems but when used with SNOMED we expect a single Refset concepts which is then evaluated for the active members of that refset.

1 June Next Time: Identify tasks required on the IG (can be raised as Git Issues to be allocated).

Potential Items for Discussion

OwnerNotes & Actions
SNOMED Family of Languages

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.
Specify CodeSystem in FSH
FSH apparently has no way of specifying the version of a CodeSystem. Daniel checking the ANTLR spec.
API for FHIR Resource ↔ Post coordinated expression mapping

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?
Looking up an SCTID in an unknown module

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://


See Discussion on Global Patient Set (GPS)
FHIR Shorthand


$lookup operation - properties returned

Using  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 Should we create a Jira TIcket to add this?

Completed -

Use of url parameter15

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 = allows for the version URI to be used as stated in The base URL is either , 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

ECL in the Valueset Expression Extension10

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 Lookup10

What properties are returned?

Discussion: Both Ontoserver and Snowstorm are returning EffectiveTime which is not listed here (unlike other SNOMED specifics):

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

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

Concluded Discussion

See also FHIR Terminology Services Discussions

OwnerNotes & Actions
Terminology Capabilities

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

New parameters proposed for streamlining operation of expand and validate code
Grahame Grieve


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.

FHIR Server Federation10

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.

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