13.157.1

• the US Core SFCU extension as defined does not include supportingInfo 

which is important to understanding the meaning of SFCU http://hl7.org/fhir/2022Sep/extension-patient-sexforclinicaluse.html.  Suggest comparing and contrasting the two extensions

• The extension and element name should not be sex for clinical use - avoid potential confusion with the FHIR R5 SFCU
• The US Core extension is defined only for Patient whereas the R5 SFCU extension may be used on many resources
• The US Core SFCU code system is not the applicable vocabulary standard as defined in USCDI v3 - providing a mapping to SNOMED CT is interesting, but by having a separate code system that is very close to that in terms of concepts to the one proposed in FHIR R5 sends the message that this extension is the same as the proposed FHIR R5 extension - and its not. Its similar, but not the same. 

• I realize these issues might not become issues until FHIR R5 is published, and that this version of US Core is based on FHIR R4, however there are probably adjustments that can be made to clarify the intended use and path forward. |