Introducing SNOMED to a FHIR audience and FHIR to a SNOMED Audience!Explanation of 4 levels of binding.
Code, Coding, Codeable Concept as specific to SNOMED CT (include link to introduction and points about display terms & multiple languages).
http://build.fhir.org/profiling.html
Many resources specify a "code" element which is the obvious location for a SNOMED CT code and this should be used where feasible. However, other fields may exist (often with multiple cardinality) that could potentially conflict or extend the meaning given by the code field. For example, in the Procedure Resource as well as the code, a message can supply (potentially multiple) bodysite codeable concepts.
So where a body site is NOT a child of the body site specified in code, what behaviour is expected?
Comment - issues with lack of relationship grouping (eg device with bodysite where multiple exist) and inability to specify whether the site is being accessed in a direct or indirect manner. We could, potentially, suggest enhancements to FHIR to bring its model into line with that of SNOMED to allow it to accurately state meaning using SNOMED CT concepts in an atomic manner, but what benefit would this give (plus ongoing maintenance overhead) when compared to using SNOMED CT in the first place?
4.2.1.0 Using SNOMED CT with FHIR
SNOMED CT canonical CodeSystem resource
See also https://simplifier.net/guides