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Grahame: The FHIR community prefers a different system than http://snomed.info/sct (which is what the specification currently says), as it makes it easier to differentiate the legacy identifiers. The FHIR Community also prefers that something exist at http://snomed.info/srtcsrt (if chosen) that is able to (a) describe what codes are valid and (b) provide some search or enumeration of all valid codes
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I notice on this page - http://build.fhir.org/terminologies-systems.html - that FHIR uses hl7/fhir URIs for a range of different code systems that don't have URIs - e.g. http://hl7.org/fhir/sid/icpc-2 and http://hl7.org/fhir/sid/ndc. Perhaps the same can be done for SNOMED 3.x and other deprecated code systems? For example http://hl7.org/fhir/sid/s3x. The only reason that this should be necessary for SNOMED RT is if an implementation uses SNOMED RT extension codes ... but if so, then something like http://hl7.org/fhir/sid/srt could be used. The documentation should also clearly indicate the deprecated status of these code systems. It may also be useful to add something to the 'Using SNOMED CT with FHIR' page (now https://terminology.hl7.org/SNOMEDCT.html ) page on the FHIR website that explains some of this history, including the deprecated nature of these code systems.
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Response from SNOMED International
"IHTSDO and its Members propose to stop issuing (directly or indirectly) licenses for the use of antecedent versions including SNOP, SNOMED, SNOMED II, SNOMED International (3.x), and SNOMED RT as of April 26th 2017 except for research purposes and to enable the interpretation of historical data captured using antecedent versions." (source)
This text states the position of SNOMED International as of 26 April 2017. Therefore SNOMED International cannot support including a URI in our specification to accommodate continued use of unlicensed, antecedent versions of SNOMED CT. Those who choose to send legacy SNOMED data have an obligation to provide a link to the appropriate SNOMED CT concept using the simple map provided by SNOMED International.
SNOMED International does not support further use of these antecedent versions of SNOMED CT in any value set or specification. If HL7 International finds it is necessary to allow these legacy SNOMED identifiers to be exchanged in FHIR resources, then a FHIR-specific URI should be created for this purpose. At the same time, it should be made clear that antecedent versions of SNOMED should not be used in any FHIR implementation that supports current data requirements.
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