More constraints on identifiers necessary

[simoneOnFhir]

In order to ascertain the proper usage of identifiers, identifier.system and identifier.value should be mandatory in general.
Where UUIDs or OIDs are required, system should be fixed to urn:ietf:rfc:3986, see: http://hl7.org/fhir/identifier-registry.html

Example: A List with

<identifier>
  <use value = "official"/>
</identifier>
<identifier>
  <use value = "usual"/>
</identifier>

...would currently validate against https://profiles.ihe.net/ITI/MHD/StructureDefinition-IHE.MHD.UnContained.Comprehensive.SubmissionSet.html

[JohnMoehrke]

so add to the MHD profiles where there are identifiers that the identifier.system and identifier.value are 1..
right?

[simoneOnFhir]

Yes. I don't see how an identifier without a value or a system would make any sense, if the identifier itself is mandatory.
Also, where OIDs or UUIDs are required, identifier,system should have a fixed value of urn:ietf:rfc:3986.
It is my observation, that that's something implementers often get wrong when using OIDs/UUIDs