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Screening Tests

Several tests can be used alone or in combination to screen for colorectal cancer.

Fecal Occult Blood Test (FOBT)
This test checks for occult (hidden) blood in the stool. At home, you place a small amount of your stool from three consecutive bowel movements on test cards. You return the cards to your doctor's office or to a lab where they're checked for blood. This test is recommended yearly. (If blood is found, you likely will need a follow-up colonoscopy.)

Flexible Sigmoidoscopy
Before this test, you use a strong laxative and/or enema to clean out the colon. Flexible sigmoidoscopy is conducted at the doctor's office, in a clinic or at a hospital. The doctor (or other specially trained healthcare professional) uses a narrow, flexible, lighted tube to look at the inside of the rectum and the lower portion of the colon. During the exam, the doctor may remove polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every five years. (If polyps are found, you will need a follow-up colonoscopy.)

Combination of FOBT and Flexible Sigmoidoscopy
Some doctors recommend having both the FOBT and flexible sigmoidoscopy to increase the chance of finding polyps (abnormal growths) and cancers. When used in combination, FOBT is recommended yearly and flexible sigmoidoscopy is recommended every five years.

Colonoscopy
Before this test, you will take a strong laxative to clean out the colon. Colonoscopy is conducted in a doctor's office, in a clinic or at a hospital. Often, you are given a sedative to make you more comfortable during the test. You are advised not to drive or work on the day of the exam, because the sedative may make you sleepy, and most doctors will not perform a colonoscopy unless you have someone with you who will accompany you home. During the exam, the doctor uses a narrow, flexible, lighted tube to look at the inside of the rectum and the entire colon. This test is similar to flexible sigmoidoscopy, except that the tube used is longer and allows the doctor to see the entire colon. During the exam, the doctor may remove polyps (abnormal growths) and collect samples of tissue or cells for closer examination. This test is recommended every 10 years. (Colonoscopy is also used as a follow-up test if anything unusual is found during one of the other screening tests.)

Double-Contrast Barium Enema
This test is conducted in a radiology center or at a hospital. Before the test, you use a strong laxative and/or enema to clean out the colon. For this procedure, you are given an enema with a barium solution, followed by an injection of air. An X-ray of the rectum and colon is then taken. The barium coats the lining of the intestines so that polyps and other abnormalities are visible on the X-ray. This test is recommended every five years. (If polyps are found, you will need a follow-up colonoscopy.)

For Patients

Screen for Life Detailed Facts on Screening (PDF-180KB) (fact sheet)

For Physicians

Screen for Life Health Professionals Facts on Screening (PDF-191KB) (fact sheet)