A colonoscopy is a test that allows your doctor to look at the inner lining of your large intestine using a thin, flexible tube called a colonoscope. A colonoscopy helps find ulcers, colon polyps, tumors, and areas of inflammation or bleeding. During a colonoscopy, tissue samples can be collected and abnormal growths can be taken out. Colonoscopy can also be used as a screening test to check for cancer or precancerous growths called polyps in the colon or rectum.
The colonoscope is a thin, flexible tube that ranges from 48 in. (125 cm) to 72 in. (183 cm) long. A small video camera is attached to the colonoscope so that your doctor can take pictures or video of the colon. The colonoscope can be used to look at the whole colon and the lower part of the small intestine. A test called sigmoidoscopy shows only the rectum and the lower part of the colon.
Before this test, you will need to clean out your colon following your doctors prep instructions. This typically involves a clear liquid diet for a period of time and drinking a special solution on the night before your procedure.