Union of http://terminology.hl7.org/CodeSystem/C5 and http://terminology.hl7.org/CodeSystem/C5
This is the CodeSystem that contains all the codes in CPT-5 (http://terminology.hl7.org/CodeSystem/C5) and CPT-5 (http://terminology.hl7.org/CodeSystem/C5). E.g. what you have to deal with if you get resources containing codes in either of them