Skip to Content



Paul H. Chung

, MD, Sidney Kimmel Medical College, Thomas Jefferson University

Last full review/revision May 2020| Content last modified May 2020

A doctor can diagnose some disorders of the bladder and urethra (for example, bladder tumors, stones in the bladder, benign prostatic enlargement) by looking through a flexible viewing tube (cystoscope, a type of endoscope). A cystoscope has a diameter about the size of a pencil, and about 6 to 12 inches (15 to 30 centimeters) of the scope are inserted into the urethra and bladder. Most cystoscopes are fiber-optic and contain a light source and a small camera, which allows the doctor to view the inside of the bladder and urethra. Many cystoscopes also contain tools that allow the doctor to obtain a sample (biopsy) of the bladder lining.

Cystoscopy can be done while a person is awake and causes only minor discomfort. The doctor usually inserts an anesthetic gel into the urethra before the procedure. Possible complications include minor bleeding and infection.

(See also Evaluation of Kidney and Urinary Tract Disorders.)

Copyright © 2022 Merck & Co., Inc., known as MSD outside of the US, Kenilworth, New Jersey, USA. All rights reserved. Merck Manual Disclaimer