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Abnormal Fecal Occult Blood Test (FOBT) Result and Recommended Colonoscopy Follow-Up

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A fact sheet for people who have received a letter from ColonCancerCheck with an abnormal FOBT result. Printable version also available:

Abnormal FOBT Result

What does my abnormal FOBT result mean?

The FOBT can detect very small amounts of blood in your stool (poop) that may be caused by cancer in the colon. An abnormal FOBT result does not necessarily mean that you have colon cancer, but additional testing with a colonoscopy is needed to find out why there is blood in your stool.

What can I expect after an abnormal FOBT result?

A colonoscopy is the follow-up test for an abnormal FOBT. ColonCancerCheck, Ontario’s colon cancer screening program, recommends that you have a colonoscopy within eight weeks of your abnormal FOBT result.

Why is it important that I have follow-up testing after an abnormal FOBT result?

Only a colonoscopy can tell you if you have colon cancer.

  • The FOBT cannot tell the difference between bleeding from colon cancer and bleeding from other sources (for example, bleeding from hemorrhoids or gums).
  • An abnormal FOBT result could mean you have colon cancer, even if you feel healthy.
  • An abnormal FOBT result could mean you have colon cancer, even if no one else in your family has had the disease.
  • Even if you have had normal FOBT results in the past, a new abnormal result means something has changed and you need a colonoscopy to find out why you have blood in your stool.

A colonoscopy can help protect your health. If colon cancer is caught early with a colonoscopy, 9 out of 10 people with the disease can be cured. If you have colon cancer and do not get tested, you may miss out on the chance for early and more effective treatment.

Colonoscopy: Follow-up for an Abnormal FOBT

What is a colonoscopy?

A colonoscopy is an exam done by a doctor to look at the lining of your rectum and colon using a long, flexible tube with a tiny camera on the end. During the colonoscopy, the doctor can also take biopsies or remove abnormal growths.

What should I expect from the colonoscopy experience?

The colon (large intestine) is the last part of the digestive system. It’s a hollow tube, four to six feet long, starting at the small intestine and ending at the rectum.

A colonoscopy is safe – it usually lasts half an hour and you can receive medication (a sedative) to make you comfortable.

The day before your colonoscopy:

To ensure a high-quality, complete colonoscopy, you must prepare for the procedure the day before. You will have to “flush out” your colon by drinking a laxative preparation (bowel preparation). This will ensure your colon is empty and clean so it can be properly examined. Before your colonoscopy, you will receive instructions about what laxative to take, any medications you should stop taking, and what you can eat and drink.

The hours after your colonoscopy:

After your colonoscopy, you will be monitored closely while the effect of the sedative wears off. You will need someone to take you home – you cannot drive a car following the sedation. You may feel a little bloated or have gas for a few hours. Gradually increasing activities, such as walking, will help you pass the gas. You may also see a small amount of blood with your first stool.

What happens after my colonoscopy?

You will receive your colonoscopy results from either the doctor who performed your colonoscopy or your family doctor. 

Normal colonoscopy:

If you had a colonoscopy because of an abnormal FOBT and your colonoscopy was normal (no abnormalities found), ColonCancerCheck recommends that you start screening again in 10 years using the FOBT.

A polyp is a small growth attached to the bowel wall, which, over time, can occasionally become cancer. If polyps are found they are usually removed during a colonoscopy and sent for analysis.

Abnormal colonoscopy:

Abnormalities, such as polyps, cancer or other colon health issues, may be found during your colonoscopy. Your doctor will notify you of your test results and next steps, including referrals for any further tests and/or treatment.

What are the risks and complications of a colonoscopy?

Only a colonoscopy can tell you if you have colon cancer. Colonoscopy is a safe procedure and complications are rare, but they can occur.

Complications may include:

  • a reaction to the medication used to sedate you
  • a very small risk of perforating (making a hole in) the colon, which may require surgery to repair
  • bleeding from removal of a polyp or abnormalities
  • missing an abnormality

Learn more about colon cancer screening

Last modified: Mon, Feb 09, 2015
cancer care ontario | action cancer ontario   620 University Avenue Toronto Ontario, Canada M5G 2L7   Phone: 416.971.9800 Fax: 416.971.6888

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