For example of how mCODE models bodySites, see http://build.fhir.org/ig/HL7/fhir-mCODE-ig/branches/master/StructureDefinition-onco-core-PrimaryCancerCondition.html . The reviewer advocates using the CIMI body location extension (see http://models.opencimi.org/ig/skin-and-wound-fhir-profiles/StructureDefinition-BodyLocationExt-definitions.html ). Similar to GF#24526, there is a risk of aligning to any pre-publication profile or extension, because it could change prior to or as a result of the balloting process. The other option would involve waiting for publication of CIMI body location extension, but that would cause unnecessary delay to mCODE. That said, it is not clear if mCODE should adopt the CIMI body location extension. The point here is not to review CIMI's work. But it is worth pointing out that the extension appears to be designed for wounds (binding to Wound Anatomic Location value set ). It duplicates rather than extends Observation.bodySite code, and does not use the FHIR laterality value set ( https://www.hl7.org/fhir/valueset-bodysite-laterality.html ). There may be other issues that could come out later during the balloting process. Proposed Resolution: Not persuasive