We have a use case where we need to know why a health card number is not present to determine if this is something that needs to be pursued or not.
We would like to use the "data absent reason" extension for patient.identifier.
1) Use "unknown" for those cases where it is expected that a patient should have a valid health card number.
2) Use "not applicable" for those cases where it is not expected that a patient would have a valid health card number (e.g. non-resident of Canada).
Currently, "not applicable" is not part of the value set for data absent reason and binding is set to "required". Can we pre-adopt inclusion of "not applicable" in the value set/code system?