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Colonoscopy

Colonoscopy is the inspection of the entire large intestine (colon) using a long, flexible, lighted viewing scope (colonoscope), which is usually linked to a video monitor. A colonoscopy may be done to screen for cancer or to investigate symptoms, such as bleeding.

Colonoscopy is done in the hospital or a doctor's office that has the necessary equipment. Preparation for the test includes emptying the bowels ahead of time using a laxative. The person undergoing colonoscopy is given medicine to relieve pain and to make him or her drowsy. The test usually takes 30 to 45 minutes, but it may take longer, depending upon what is found and what is done during the test.

A doctor will collect a tissue sample (biopsy) from any abnormal area. The tissue is then analyzed by a pathologist.

Colonoscopy: Overview

  • Preparing for colonoscopy

    How do you prepare for a colonoscopy?

    You need to clean out your colon before the procedure so the doctor can see all of your colon. This process may start a day or two before the test. This depends on which “colon prep” your doctor recommends.

    To clean your colon, you stop eating solid foods and drink only clear liquids. You can have water, tea, coffee, clear juices, clear broths, flavored ice pops, and gelatin (such as Jell-O). Do not drink anything red or purple.

    The day or night before the procedure, you drink a large amount of a special liquid. This causes loose, frequent stools. You will go to the bathroom a lot. It's very important to drink all of the liquid. If you have problems drinking it, call your doctor.

    Some people don't go to work or do their usual activities on the day of the prep.

    Arrange to have someone take you home after the test.

  • During the procedure

    How is a colonoscopy done?

    A colonoscopy may be done in a doctor's office, clinic, or a hospital.

    During the test, you may get a pain medicine and a sedative put in a vein in your arm (IV). These medicines help you relax and feel sleepy during the test. You may not remember much about the test.

    Before the test

    You will need to take off most of your clothes. You will be given a gown to wear during the test.

    You may lie on your left side with your knees pulled up to your belly. Because you will be given medicine during the colonoscopy, you probably won't remember much, if anything, until you wake up after the procedure.

    Next, the doctor will insert a thin, flexible colonoscope in your anus and move it slowly through the rectum and into your colon. Air will be used to inflate your colon so the doctor can look at the lining of the colon through the scope or on a computer screen hooked to the scope.

    During the test

    Your doctor will look at the whole length of your colon as the scope is gently moved in and then out of your colon. You may be asked to change your position during the test.

    The doctor may also use tiny tools, such as forceps, loops, or swabs, through the scope to collect tissue samples (biopsy) or take out growths. Usually, people don't feel anything if a biopsy is done or if polyps are taken out.

    The scope is slowly pulled out of your anus, and the air escapes. Your anal area will be cleaned with tissues. If you are having cramps, passing gas may help relieve them.

    After the test

    After the test, you may need to stay at the clinic for 1 to 2 hours. Or you may be allowed to leave sooner with the person who will drive you home.

  • After the procedure

    After a colonoscopy: Overview

    After a colonoscopy, you'll stay at the clinic for 1 to 2 hours until the medicines wear off. Then you can go home. But you'll need to arrange for a ride. Your doctor will tell you when you can eat and do your other usual activities.

    Your doctor will talk to you about when you'll need your next colonoscopy. Your doctor can help you decide how often you need to be checked. This will depend on the results of your test and your risk for colorectal cancer.

    After the test, you may be bloated or have gas pains. You may need to pass gas. If a biopsy was done or a polyp was removed, you may have streaks of blood in your stool (feces) for a few days. Problems such as heavy rectal bleeding may not occur until several weeks after the test. This isn't common. But it can happen after polyps are removed.


    opyrighted material adapted with permission from Healthwise, Incorporated. This information does not replace the advice of a doctor.