The FIT test (Faecal Immunochemical Test) is a simple stool test that checks a small sample for tiny amounts of blood not visible to the eye, which can be an early sign of bowel changes or bowel cancer. It is done at home using a kit, needs no special diet for most people, and forms the first step in bowel cancer screening. A normal result is reassuring but should be repeated as advised; an abnormal result means blood was found and usually leads to a colonoscopy. See a doctor for any bowel symptoms even if your test is normal.
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Bowel (colorectal) cancer is one of the more common cancers in Singapore, yet it often grows quietly with no symptoms in its early stages. The FIT test offers a straightforward way to look for hidden warning signs before problems become serious. This guide explains what the test is, how you do it at home, what your result means, and when you should still speak to a GP or polyclinic doctor.
What the FIT test is
The Faecal Immunochemical Test is a simple home test that checks a small stool (poo) sample for tiny amounts of blood that you cannot see with the naked eye. Small bowel growths, called polyps, and early cancers can bleed slightly, and this blood may pass out mixed in the stool long before any symptom appears. The FIT test is the modern version of the older stool blood test (sometimes called the faecal occult blood test). It is more specific because it detects human blood from the lower bowel, which is why it generally does not require the dietary restrictions the older test needed. It is not itself a diagnosis of cancer; it is a screening tool that flags who may need a closer look.
Why it is done
The main reason for the FIT test is bowel cancer screening in people who feel well and have no symptoms. The aim is to catch changes early, when treatment is simpler and more likely to succeed, or to find polyps that can be removed before they ever turn into cancer. Because early bowel cancer is so often silent, waiting for symptoms can mean it is found late. Regular screening with FIT gives a low-cost, comfortable way to keep watch over time. Less commonly, a doctor may also use a stool blood test to help assess certain bowel symptoms, though symptoms usually need direct clinical review rather than screening alone.
How to do it
The FIT test is designed to be done privately at home. You will be given a kit containing a small collection stick or probe, a sample bottle and clear instructions. In general, you collect a small amount from a single bowel motion by brushing or scraping the stick across the surface of the stool, then seal it in the bottle. It is best to avoid collecting a sample that has fallen into toilet water or is mixed with urine. For this type of test, no special diet is usually needed, so you can eat and take your medicines as normal unless your doctor tells you otherwise. Label the sample as directed and return it promptly according to the kit instructions, as leaving it too long can affect the result. If you are unsure at any step, your GP, polyclinic or the screening programme can guide you.
What happens next
Once returned, your sample is sent to a laboratory and analysed for traces of blood, and your result is sent back to you or your doctor. A normal (negative) result means no significant blood was detected. This is reassuring, but bowel changes can develop later, so screening is repeated at the intervals recommended by Singapore’s national programme. An abnormal (positive) result means blood was found in the sample. This does not diagnose anything on its own, but it does mean you should have a follow-up test to find out where the blood is coming from.
What an abnormal result means
An abnormal FIT result can feel worrying, but it is important to understand that it does not mean you have cancer. Blood in the stool has many possible causes, and most are not cancer. It can come from piles (haemorrhoids), small tears, inflammation in the bowel, or other benign conditions. What an abnormal result does mean is that the finding needs to be explained. Your doctor will usually recommend a colonoscopy, a procedure that lets a doctor look directly inside the bowel, take samples if needed and remove any polyps found. Attending this follow-up is the most important step, because it is what turns an abnormal screen into a clear answer.
Benefits and limitations
The great strength of bowel screening is that it saves lives. By finding cancer early or by allowing polyps to be removed before they become cancer, screening can prevent illness altogether or greatly improve the chances of successful treatment. It is also easy, painless and can be done at home. However, no test is perfect. The FIT test can miss some cancers or polyps, particularly if they are not bleeding at the time you collect your sample, which is why a single normal result is not a lifelong guarantee and why repeat screening matters. It can also be positive for reasons that have nothing to do with cancer, leading to further tests that turn out to be reassuring. Understanding both sides helps you use screening well without over-relying on it.
Who should consider screening
Bowel cancer screening is generally recommended for adults in the appropriate age range who have no symptoms, and the FIT test is the usual first step. Rather than deciding alone, it is best to follow Singapore’s national screening recommendations, which are supported by bodies such as the Health Promotion Board and the Singapore Cancer Society, and to speak with your GP or polyclinic doctor about what is right for you. People with a family history of bowel cancer or polyps, or with previous bowel conditions, may need a different or earlier approach, so a personal conversation with a doctor is always the safest guide.
When to see a doctor regardless
Screening is for people without symptoms, so it is not a substitute for getting symptoms checked. See a doctor promptly, even if your FIT test was recently normal, if you notice a persistent change in bowel habit, blood in your stool, ongoing tummy pain, unexplained weight loss, or unusual and lasting tiredness. A normal screening result can be falsely reassuring when symptoms are present, because a test taken on one day cannot rule out a problem developing at another time. Symptoms deserve their own assessment, and acting early always gives you the best options.
Common questions
Does a positive FIT result mean I have cancer?
No. It means blood was found in your stool sample, which has many possible causes such as piles or inflammation. It simply means you need a follow-up test, usually a colonoscopy, to find the cause.
Do I need a special diet before the test?
For the FIT test, no special diet is usually needed because it detects human blood specifically. You can normally eat and take your medicines as usual, but always follow the instructions in your kit or ask your doctor if unsure.
Is the FIT test painful or embarrassing?
No. It is a painless test you do privately at home by collecting a tiny sample from a single bowel motion. Nothing is inserted into the body, and the sample is sealed and returned discreetly.
How often should I do the test?
Bowel screening is meant to be repeated regularly because bowel changes can develop over time. Follow the intervals recommended by Singapore’s national screening programme, and ask your GP or polyclinic doctor how often applies to you.
What if my result is normal but I have symptoms?
See a doctor. A normal FIT result does not rule out a problem when symptoms are present. Any change in bowel habit, blood in the stool, tummy pain, weight loss or persistent tiredness should be assessed on its own.
Related guides
Sources
- Singapore Cancer Society
- Health Promotion Board
- HealthHub
- National Cancer Centre Singapore
Disclaimer: This guide is for general information only and is not a substitute for personal medical advice. It does not give individual recommendations. Please speak to your GP, polyclinic or a qualified doctor about screening and about any symptoms that concern you.