This is the CodeSystem that contains all the codes in Healthcare Common Procedure Coding System (HCPCS) level II alphanumeric codes (http://www.cms.gov/Medicare/Coding/HCPCSReleaseCodeSets) and Healthcare Common Procedure Coding System (HCPCS) level II alphanumeric codes (http://www.cms.gov/Medicare/Coding/HCPCSReleaseCodeSets). E.g. what you have to deal with if you get resources containing codes in either of them