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    Why It Is Done

    Colonoscopy is done to:

    • Check for colorectal cancer or polyps.
      • This test is recommended by the American Cancer Society (ACS), the American College of Gastroenterologists (ACG), the American Gastroenterological Association (AGA), and the U.S. Preventive Services Task Force (USPSTF).
      • These groups recommend routine testing for people age 50 and older who have a normal risk for colorectal cancer.
      • Your doctor may recommend earlier or more frequent testing if you have a higher risk of colorectal cancer. Talk to your doctor about when you should be tested.
    • Check for the cause of blood in the stool or rectal bleeding.
    • Check for the cause of dark or black stools.
    • Check for the cause of chronic diarrhea.
    • Check for the cause of iron deficiency anemia.
    • Check for the cause of sudden, unexplained weight loss.
    • Check the colon after abnormal results from a CT scan, MRI, virtual colonoscopy, stool test, or barium enema.
    • Watch or treat inflammatory bowel disease (IBD).
    • Check for the cause of long-term, unexplained belly pain.

    How To Prepare

    Before you have a colonoscopy, tell your doctor if you:

    • Are taking any medicines, such as insulin or medicines for arthritis. Check with your doctor about which medicines you need to take on the day of your test.
    • Are allergic to any medicines, including anesthetics.
    • Have bleeding problems or take aspirin or other blood thinners.
    • Had an X-ray test using barium, such as a barium enema, in the last 4 days.
    • Are or might be pregnant.

    You may be asked to stop taking aspirin products or iron supplements 7 to 14 days before the test. If you take blood-thinning medicines regularly, discuss with your doctor how to manage your medicine.

    You will be asked to sign a consent form that says you understand the risks of the test and agree to have it done.

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    WebMD Medical Reference from Healthwise

    Last Updated: November 14, 2014
    This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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