With the introduction of R5, the ConceptMap resource now features additional fields that can be used to convey additional information about mappings, for example the "mapRule" and "mapAdvice" columns of an extended map, like that provided for mapping from SNOMED to ICD-10. The SNOMED on FHIR group would like make a proposal for how the various SNOMED features should be represented in the R5 ConceptMap resource, so as to support wider interoperability.
Note that ICD-10 Map rules are intended to be machine readable (logic or parser should be made available for this to work in practice). Map advice is expected to be human readable. See 5.2.3.3 Complex and Extended Map from SNOMED CT Reference Sets
See also discussions eg 2024-02-20 - SNOMED on FHIR Meeting (TS & TB)
| Resource Element | SNOMED Map Feature | Discussion |
|---|---|---|
| property | Additional properties of the mapping (may previously have been called Additional Attribute). Note, does not exist in R4 so we'd need to either use product there, or an extension eg http://hl7.org/fhir/5.0/StructureDefinition/extension-ConceptMap.group.element.target.property ML Suggests that what actually matters is the result of the $translate operation and since the parameter block can contain anything, we can already use R5 elements in an R4 response | |
| additionalAttribute | "Definition of an additional attribute to act as a data source or target" | |
| sourceScope | Was source - just a change in name | |
| targetScope | ||
| noMap | Boolean to quickly say that there is no map available (previously had to create a target block and specify) | |
| target.relationship | Was target.equivalence now uses a smaller number of codes, much more descriptive. | |
| target.property | Most of the fields in the ICD-10 map are properties ie metadata about the map | |
| dependsOn | Was previously a string, now a choice of valueTypes ( 0..* cardinality) "Other properties required for this mapping" so further information that is required before a mapping can be chosen. A list of information that should be supplied before the mapping can be completed - so "gender" might be an example. The list of potential values that could be supplied may be returned in dependsOn.valueSet See table in https://build.fhir.org/conceptmap.html#dependencies , in that case the dependsOn is presented like the "context" in which the mapping should be applied eg for a diagnosis or family history. "List of additional properties (eg Age) that this mapping depends on", rather than the rule that is then applied. Available in R4, and in R4 it's a string rather than the code/coding that it is in R5. | |
| product | Has same structure as depends on. Is available in R4. Limited as has type "Coding" and we need Strings to be able to express additional columns from extended map. Explained as being "part of the target" |
Outstanding questions:
- If we are going to pass in the required additional values that are needed for the mapping (eg age, sex), then how should those be represented? Passed in as a list of dependencies see https://hl7.org/fhir/R4/conceptmap-operation-translate.html which would require using a String in R4 and in R5 we have dependency.value