CPT is an acronym for Current Procedural Terminology. CPT codes are published by the American Medical Association, and the fourth edition is the most current. The purpose of the coding system is to provide uniform language that accurately describes medical, surgical, and diagnostic services.he relationship between ICD-9 (diagnosis) and CPT (procedural) Codes. The critical relationship between an ICD-9 code and a CPT code is that the diagnosis supports the medical necessity of the procedure.