The CPT-4 (also called HCPCS [HCFA Common Procedural Coding System] Level I) coding system is a set of five-digit codes that apply to medical services rendered in physician offices, outpatient clinics or ambulatory surgery centers. They are categorized by specialty or service, and include office and hospital visits or consultations, preoperative evaluations, ancillary diagnostic services, etc. CPT codes should correlate with ICD-9 codes.

A physician should choose a code reflecting the most extensive description that is applicable to a procedure to ensure adequate payment. One also needs to be aware of gender specific codes. Billing for individual services that are components of a procedure, �unbundling,� is prohibited by Medicare and is a target for MCOs at claim processing; a ��global� charge is billed instead. If �mutually exclusive� code combinations are submitted to MCOs, they will pay for the procedure of the lowest allowable charge and deny the others. Coding and payment for non-exclusive multiple procedures will depend on whether they were related and performed at the same site and/or the same time.