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