Current Procedural Terminology (CPT) is the code set maintained by the American Medical Association (AMA) used to report medical, surgical, and diagnostic services on healthcare claims. CPT codes are five-digit numeric (with select alphanumeric Category II and III codes) and are required by virtually every U.S. payer — commercial insurers, Medicare, Medicaid, and workers' compensation carriers — to adjudicate claims. The AMA publishes annual updates each fall that take effect January 1. For occupational-health clinics, fluency in the relevant CPT subsets is essential to revenue capture: evaluation and management codes (99202–99215 for new and established office visits), spirometry (94010, 94060), audiometry (92551 screening, 92552 threshold), respirator fit-testing (no dedicated CPT — typically billed as an E/M or with HCPCS), drug screening (80305 presumptive, 80306 with read-by-instrument, 80307 confirmatory), venipuncture (36415), and immunization administration (90460–90474). Many occ-med encounters are billed direct-to-employer (cash) rather than through insurance, but CPT coding remains the lingua franca for charge masters, audits, and any payer-facing work.