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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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