HL7AU - FHIR WG : Pros and Cons relating to use of SNOMED CT or LOINC in value sets bound to coded elements in FHIR profiles

Created by Reuben Daniels, last modified on 24 Sep, 2018

This page is intended to solicit discussion from participants in the Child Health WG around the pros and cons of either terminology. Please add your pros and cons as a comment. Optionally, you may update the summary table if yours pros and cons have not been captured or one of the co-chairs will do so.


TerminologyProsCons
SNOMED CT-AU
  • Content managed by the ADHA / NCTS clinical terminology team (including addition of new content).
  • Based on the SNOMED CT international standard adopted by multiple countries making adoption of international content possible.
  • New content can be added with quick turnaround time.
  • Officially supported as an NCTS content type.
  • Supported by the CSIRO Ontoserver terminology server.
  • Use with FHIR mature and a focus of both Standards Development Organisations (HL7 International and SNOMED International)
  • Increasingly being adopted by jurisdictions.
  • Licensing free in Australia
  • Growing, but not broad adoption in Australia
  • Challenging to adopt natively - helped through use of FHIR and the NCTS
LOINC
  • Supported by existing FHIR profiles from the USA
  • Supported by the CSIRO Ontoserver terminology server.
  • Free for use in Australia
  • Scope of content is more limited than SNOMED CT-AU
  • Not yet an NCTS supported content type.
  • Single release managed in the USA, making it more difficult to have new content added.

Comments:

In general, my view is that there are quite a number of strong arguments for the use of SNOMED CT-AU as the primary coding system for implementation guides like those being produced by the Child Health WG. That said, we do have significant adoption of LOINC in some areas and thus there will be cases were that should be the specified coding system e.g. pathology requests.

SNOMED CT-AU

Pros

  • The the ADHA / NCTS, we have a dedicated team team of terminologists and experts supporting the use of SNOMED CT-AU in Australia.
  • SNOMED CT-AU includes a broad and comprehensive set of clinical content and with over 30 member nations, is a truly international standard. Through representation in SNOMED International, content from other national editions can potentially be included in SNOMED CT-AU with little modification.
  • Requests for new content can be processed by the NCTS team and included SNOMED CT-AU releases with a quick turnaround time. This includes creation of new concepts (and identifies), national/3rd party SNOMED CT reference sets, and FHIR Value Sets based on SNOMED CT content.
  • SNOMED CT terminologies (like SNOMED CT-AU) are supported as an NCTS Content Type and thus have strong support in NCTS national infrastructure services, technical specifications, and conformant applications.
  • CSIRO Ontoserver has advanced support for SNOMED CT terminologies (including SNOMED CT).
  • SNOMED CT is well supported by the FHIR standard through work in HL7 International and SNOMED International. Specifically, the joint HL7/SNOMED International SNOMED-on-FHIR working group collaboratively ensures the standards can work together. 
  • Increasing number of jurisdictions are adopting SNOMED CT-AU. For example, SNOMED CT-AU is adopted in Queensland Health's state-wide Cerner-based Integration Electronic Medical Record (iEMR)
  • SNOMED CT-AU licenses are free in Australia (through Australia's membership of SNOMED International)

Cons

  • Although increasing, Australia does not yet have broad adoption of SNOMED CT-AU in clinical information systems. This adoption of SNOMED CT-AU in profiles may require some mapping.
  • Adopting SNOMED CT-AU natively remains challenging, though this is simplified through the use of FHIR and the NCTS.


LOINC

Pros

  • Supported by existing FHIR profiles from the USA which may be helpful to adopt, where possible, without modification.
  • The CSIRO Ontoserver terminology server supports LOINC.
  • LOINC is free for use.

Cons

  • The scope of LOINC is far less comprehensive that SNOMED CT. Thus for many use cases, it may not be suitable as the primary coding system.
  • Whilst on the roadmap to become an NCTS supported coding system, it is currently not one. Accordingly, national infrastructure services (e.g. the National Syndication Service) and technical specifications (e.g. NCTS Content Types and Conformant Server Applications specifications) do not currently LOINC.
  • As a single terminology release (i.e. no national extensions) managed in the USA, it is non-trivial to get new content added to LOINC.
Posted by reuben at 24 Sep, 2018 13:32

To contribute to the discussion, above a view point from a researcher into the clinical terminology space and worked / working with the LOINC - SNOMED CT collaboration and mentioned his view on the use of LOINC (observables) to SNOMED CT (coded result values):

https://danielvreeman.com/guidelines-for-using-loinc-and-snomed-ct-together-without-overlap/
Posted by jose.veroes at 13 Nov, 2018 15:25

We can reasonably allow both SNOMED CT and LOINC in FHIR profiles as almost all places where terminology is used in FHIR resources the data element is of type CodeableConcept. This allows a value to be sent in both SNOMED CT and LOINC.

We could choose SNOMED CT as a preferred terminology, and still use LOINC in local profiles of FHIR international profiles that mandate LOINC, such as BodyWeight. We can mandate the SNOMED CT equivalent in an Australian profile.
Posted by richard.townleyoneill at 11 Dec, 2018 14:56