CPT Code Categories: Complete Medical Billing Reference Guide

CPT codes are five-digit numeric codes maintained by the American Medical Association that identify every medical procedure and service provided in a clinical setting. Selecting the correct code is a foundational step in medical coding, the wrong code, missing modifier, or unsupported documentation triggers denials, payment reductions, and compliance risk.

This reference organizes all CPT code categories by section, covering code ranges, the most frequently billed individual codes, and guidance on applying them correctly across specialties. Each category entry includes the codes most relevant to day-to-day billing and the documentation requirements that determine whether a claim pays on first submission.