In context of https://jira.hl7.org/browse/FHIR-28375 we propose that the Reference list be limited to US Core Practitioner Profile and all other base standard choices be optional.

A Practitioner reflects the role who would be creating a note.  Within the current scope of USCDI and the use of FHIR, patients would not actually create clinical documents for themselves (they can contribute data, but a practitioner would be involved in making that part of the record).  If and when patient generated document note writes are required scope, then a Patient would be required.  As write operations are not in scope in the g(10) criterion in the final rule, it should be optional along with other choices allowed by the base standard.

As the FHIR US Core profile is used for accessing and exchanging data based on what the source system has, this should not require the data source system to add functionality to capture a patient as part of the document reference.  Additionally, C-CDA does not impose this requirement either.

Links to pages:

http://hl7.org/fhir/us/core/STU3.1/StructureDefinition-us-core-documentreference.html

https://build.fhir.org/ig/HL7/US-Core-R4/StructureDefinition-us-core-documentreference.html