Sorry if this is a beginner question, but I can't seem to get a straight answer from the docs.

When we specify an id, in patientRole for example, must we use a valid HL7-registered OID for the root value?

We are adding Meaningful Use capabilities to our software, but I'm not sure if we use our own OID, or that of the health provider, or the insurance provider, or whatever.

I understand that the combination of the id and extension must be unique, but I don't know if this should be the id for the hospital with an MRN in the extension, or our OID along with some DB ref for the patient entity.

Is there a best practice?