Key Identifiers

All identifiers used in FHIR messages must have a "system" as well as a "value". Systems do not exist in CPHA but are necessary to guarantee uniqueness and therefore must be managed when implementing FHIR. For backward compatibility, systems are optional in the FHIR profiles, though it is recommended that systems are derived or assigned fixed values when mapping from CPHA, wherever possible.

Implementers should familiarize themselves with this data type. https://hl7.org/fhir/R4/datatypes.html#Identifier

Identifiers to be managed by Adjudicators

1. Organization.identifier:PharmacyIDCode.system. This is the CPHA Pharmacy ID Codes. A "system" is required in FHIR and must be assigned by each adjudicator. This is typically a fixed value that must be conveyed to vendors.
   
2. Claim.response.identifier. As the CPHA Reference number is restricted, FHIR has a new identifier for the response that is unrestricted. A "system" must be assigned.

Identifiers to be managed by POS

1. Claim.identifier. This is new for FHIR in addition to the Trace Number (6N). A "system" is required and must be assigned by the software vendor. This is limited to 9N as it is often the same identifier as the Current RX Number.
2. Trace Number. This is mappable to the existing Trace number. This is limited to 6N.
3. Current RX Number. No changes from CPHA3 usage

Code System Identifiers

Code System Identifiers are found in the FHIR profiles as fixed values, where applicable. They are also listed in the terminology page of this specification, found here