A colonoscopy is a procedure performed under sedation that allows a gastroenterologist to examine the lining of your large intestine, or colon. A thin, flexible, lighted instrument with a camera on the end, called a colonoscope, is used to visually inspect your colon for any bleeding, inflamed tissue, ulcers, and abnormal growths such as colon cancer or polyps. Images of the colon are viewed on a video screen. When polyps are found, they are removed and sent to a lab for testing. Not all polyps found at a screening colonoscopy are precancerous, but over time, precancerous polyps can grow and become cancer.
You will be given instructions for a clear liquid diet with laxative preparation to ensure your bowels can easily viewed during the exam. An IV line will be inserted in your arm so you may be given sedation medications. When the physician begins the exam, you will be asked to lie on your left side and then the colonoscope is gently inserted into your rectum and gradually advanced through the inside of your colon. During the exam, your physician is able to distend the colon for improved visibility, remove polyps or take biopsies. The exam generally takes 20-30 minutes.
More information about colonoscopy at asge.org