Transformations to Normal Forms
The requirements for full normalization of alternative representation using different combinations of SNOMED CT and HL7 RIM artifacts requires an agreed comprehensive reference normal form. This is beyond the scope of this document. However, the rules and guidance in Guidance on Overlaps between RIM and SNOMED CT Semantics provide the foundations for specifying some of the more common transformation requirements.
In particular the following types of transformation may be required
- Transforming deprecated patterns using the Observation.code and Observation.value to the preferred pattern. See Act.code and Observation.value and Observation code and value (in event mood)
- Transforming based on moodCode and statusCode to apply specified contexts to SNOMED CT expressions, where these expression do not state an explicit context. See Act.moodCode and Act.statusCode.
- Transforming any deprecated uses of the negationInd attribute to an appropriate SNOMED CT expression that explicitly state appropriate "finding context" or "procedure context". See Act.negationInd.
- Transforming any information in specific HL7 methodCode, targetSiteCode and approachSiteCode attributes into the appropriate refinements of the associated SNOMED CT expression. See Procedure.methodCode and Observation.methodCode, Procedure.targetSiteCode and Observation.targetSiteCode and Procedure.approachSiteCode and SubstanceAdministration.approachSiteCode.
- Transforming the representation of "subject" participation and SNOMED CT "subject relationship context" into a single coherent form. See Subject Participation and Subject Relationship Context.
Additional documentation on this topic will be added based on experience of use of this specification.