What are the component of an an HCPCS coding system?

There are three components to the overall structure of the HCPCS system:

1. HCPCS National Level I, the major portion of the system, consists of the CPT codes. These codes primarily define the physician procedures and services performed during the work-up and treatment of patients.

2. HCPCS National Level II, or plain HCPCS codes. These codes primarily describe supplies and materials such as durable medical equipment, injections, and IV medications, along with a handful of patient treatments not covered in the CPT codes.