Screening with a Faecal Occult Blood Test (FOBT)
A FOBT is a simple, non-invasive test that can be completed in your own home. The test detects tiny amounts of blood, often released from bowel cancers or their precursors (polyps or adenomas) into the bowel motion.
What type of FOBT is used in the Program?
There are two main types of FOBT - guaiac and immunochemical tests. This phase of the National Bowel Cancer Screening Program is using an immunochemical FOBT called 'Detect™'. The answers below are accurate for 'Detect™'. An immunochemical FOBT is being used because, in contrast to Guaiac FOBTs, they have no potential for interference by diet or medication, and are considered to be less intrusive, more reliable, more acceptable and more likely to achieve higher participation rates.Top of Page
What does the FOBT involve?
The FOBT is a simple test that can be done at home before sending it to a pathology laboratory for analysis. The test is quick, easy and painless. To increase the chances of detecting tiny amounts of blood in the bowel motion, samples are taken from two separate bowel motions. Because the test involves taking separate samples, it is not practical to do the test at a doctor’s surgery. Once both samples are collected they are returned by post to a pathology laboratory for analysis.Top of Page
How accurate/effective is a FOBT?
Like any screening test, a FOBT is not 100% accurate.However, it is currently the most well researched screening test for bowel cancer.
Because cancers and precancerous growths only bleed intermittently it is possible that the FOBT will miss one. This is why it is important to screen regularly and see a doctor if symptoms develop, regardless of the FOBT result.
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Why do two samples need to be provided?
As cancers and precancerous growths only bleed intermittently, providing two samples helps to ensure a more accurate FOBT result.Top of Page
Is a special diet required before collecting the samples?
No. It is not necessary to change your diet in any way.Top of Page
Are there any restrictions for medication?
No. It is not necessary to avoid taking any medicines before the sample collection. The test is specific for human blood, so the test is not affected by medicines.Top of Page
Are there any restrictions on when samples cannot be collected?
Yes. Samples cannot be collected if:- it is during or within 3 days either side of a menstrual period;
- haemorrhoids (piles) are bleeding; or
- blood is present in the urine or visible in the toilet bowl – in this case contact your doctor.
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What will happen to the FOBT results?
The results will be sent to the person completing the test and to their doctor (if they have nominated one). The result is also sent to the National Bowel Cancer Screening Program Register. People will generally receive their test result about two weeks after posting the completed test to the pathology laboratory.Top of Page
What does the FOBT show?
If no significant blood is found in the samples the FOBT result is negative. People who receive a negative result should repeat a FOBT in two years. If they have or develop symptoms (or become aware of a significant family history of bowel cancer) they should see their doctor as soon as possible.If significant levels of blood are present in the samples the FOBT result is considered positive. About one in 14 people will have a positive result. The presence of blood may be due to conditions other than cancer, such as polyps, haemorrhoids, or inflammation of the bowel, but the cause of the bleeding needs to be investigated. People with a positive FOBT result will be advised to contact their doctor to discuss the result.
An inconclusive or incomplete FOBT result may occur for a number of reasons, including incorrect use of the test, too much faeces in the samples, a significant delay between taking the two samples or a delay in sending the test to the pathology laboratory. People who have an inconclusive or incomplete FOBT result, will be sent a replacement kit by the Register and asked to complete the test again.
Page currency, Latest update: 07 July, 2008