CPT code 45305 denotes a diagnostic proctosigmoidoscopy performed with biopsy of the distal colon, rectum, or anus. This code captures a commonly used endoscopic procedure that combines visual evaluation of the anorectal canal and sigmoid colon with tissue sampling to support diagnosis of inflammatory, infectious, neoplastic, or other mucosal disease. Nationally, the code is important for gastroenterology, colorectal surgery, and primary care referral workflows where targeted mucosal assessment and histologic confirmation guide treatment decisions.

Key payers referenced in this analysis include Aetna, Blue Cross Blue Shield, Cigna Health, UnitedHealthcare, and Medicare. Readers will find an overview of typical clinical indications and sites of service, common billing and coding considerations tied to procedural documentation, and benchmarking context where available. The publication outlines typical payment and coverage themes across major payers, highlights clinical scenarios that affect code selection, and summarizes documentation elements that commonly influence claims adjudication.

The content provides clinicians, coding professionals, and policy analysts with concise clinical context, payer coverage scope, and the types of benchmarks and policy updates to watch for when using CPT code 45305 in practice.