Faecal Occult Blood Test

Written by Ali Zarrouk on .

What is the Faecal Occult Blood Test?

The Faecal Occult Blood Test (FOBT) is the examination of stool samples from two separate bowel movements for taces of blood that are not visible to the naked eye. The test is done at home using a test kit and the samples are then sent to a laboratory for testing.
Blood in stool may be a sign of an early bowel cancer or a polyp ( a precancerous growth). It the FOBT is positive then a colonoscopy is needed to examine the bowel fully.

How accurate is the FOBT?

The test is 40% to 80% accurate in detecting all colon cancers. Having the FOBT every two years can reduce the risk of dying from bowel cancer by one third. The test can miss colon cancer as the cancer may bleed on and off.

Who should have an FOBT?

People aged over 50 without symptoms and without strong family history of bowel cancer should do the test every two years.
People with bowel symptoms or with personal or strong family history of bowel cancer should see a specialist for assessment and a have a colonoscopy.

Why are the samples collected on different days?

Colon cancer and polyps may bleed on and off therefore, having two samples at different days increase the likelyhood of picking up the blood in the stool.

What does a negative FOBT means?

A negative result does not mean that you do not have a bowel cancer since the cancer may bleed every now and then. The test should be repeated in two years.

What does a postive FOBT means?

There are several causes for blood in the stool other than bowel cancer or polyps, e.g bleeding piles, menstrual blood, bowel inflammation ..etc.
If the test is positive then it is important to see your doctor for a referral for a colonoscopy.

I am having bowel troubles now can I have the FOBT to check my bowel?

No. The FOBT is a screening test for people who do not have symptoms or have a strong family history of bowel cancer. Patients who have bowel symptoms should be assessed by a specialist and have a colonoscopy. A negative FOBT can provide a false reassurance and delay the diagnosis of potentially a serious problem.


Click here to read about colonoscopy

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