Colonoscopy

What Affects the Test

Reasons you may not be able to have the test or why the results may not be helpful include:

• Having a barium enema a week before the test. Barium can block your doctor's view of the colon.
• Having stool (feces) in the colon, a colon that has many turns, past surgery on the colon, or a lot of pain during the test.
• Taking iron supplements. This may make your stool turn black and make it hard to clean out the colon. Do not take iron supplements for several days before a colonoscopy.
• Drinking red fluids or eating red gelatin. This can change the color of secretions in the colon and may be mistaken for blood.

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Author:	Monica Rhodes	Last Updated: September 1, 2006
Medical Review:	Kathleen Romito, MD - Family Medicine Peter J. Kahrilas, MD - Gastroenterology
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