The Official UB-04 Data Specifications Manual 2021, copyrighted by the American Hospital Association, is the only official source of UB-04 billing information adopted by the National Uniform Billing Committee (NUBC). No other publication—governmental or private/commercial—can be considered authoritative. It contains updated specifications for the data elements and codes included on the UB-04 claim form, and used in the electronic HIPAA Institutional 837 Health Care Claim transaction standard.