FIT Test vs Colonoscopy

How the FIT Test Works 

The Faecal Immunochemical Test (FIT) kit is a non-invasive screening tool that checks for small amounts of blood in the stool. This blood is often not visible to the naked eye and may indicate underlying colorectal abnormalities. The test is done at home using a kit provided by a clinic and usually requires only a single stool sample. There are no dietary restrictions or medication changes needed, which makes the process straightforward and convenient for most people.

The FIT kit is commonly offered to average-risk individuals by participating clinics in Singapore under the Healthier SG programme. It is typically recommended for adults aged 50 and above who do not have symptoms such as persistent rectal bleeding, unexplained weight loss, or significant changes in bowel habits. For many people, the FIT kit serves as a practical starting point for colorectal screening.

It is important, however, to understand the limitations of the FIT kit. Because it detects bleeding rather than directly examining the colon, it might miss polyps or early cancers that are not bleeding at the time of testing. A positive FIT result does not necessarily mean cancer is present, but it does mean further evaluation is needed. This is usually when a colonoscopy is recommended.

Why Colonoscopy Remains the Gold Standard

A colonoscopy allows the doctor to examine the entire colon directly using a flexible camera. This means abnormalities such as polyps, inflammation, or early cancers can be seen clearly, rather than inferred from indirect signs like bleeding. During the same procedure, tissue samples can be taken and polyps can be removed immediately, which helps reduce the risk of these growths developing into cancer later on.

While many people worry about the invasive and often uncomfortable nature of the procedure, colonoscopy is usually performed under sedation, colonoscopy is usually performed under sedation. For those of us who want a clearer picture of our colorectal health, colonoscopy offers a single, thorough assessment rather than repeated testing over time.

Colonoscopy is commonly recommended for individuals with symptoms such as rectal bleeding, unexplained anaemia, or changes in bowel habits. It is also the next step after a positive FIT kit result. Colonoscopy remains the most comprehensive option for colorectal screening and evaluation, as it allows both diagnosis and treatment in a single setting.

FIT Kits vs Colonoscopy

When deciding between a FIT kit and colonoscopy, it helps to look at how the two differ in what they can detect. FIT kits are designed to pick up traces of blood in the stool, which can be an early sign of colorectal abnormalities. However, if a polyp or early cancer is not bleeding at the time of testing, it may not be detected. Colonoscopy, on the other hand, allows direct visual examination of the colon, making it more accurate at identifying polyps and early-stage cancers regardless of whether bleeding is present.

Because of this difference in accuracy, screening recommendations are not the same for everyone. If you have a personal history of colorectal cancer, you should follow a specialist-led monitoring plan, which often includes colonoscopy, rather than relying on routine FIT kit screening. This approach allows closer monitoring and timely intervention when needed.

Risk and convenience are also important considerations. FIT kits are non-invasive, can be done at home, and carry virtually no procedural risk, which makes them appealing as a first step for many average-risk individuals. Colonoscopy is more invasive and requires bowel preparation and sedation, but it also provides a more definitive assessment by allowing immediate treatment if abnormalities are found.

Cost and testing frequency further differentiate the two options. FIT kits are relatively low-cost and are usually recommended on a yearly basis. Colonoscopy has a higher upfront cost but is performed less frequently when results are normal. Weighing these factors together helps clarify which screening approach best fits your health needs and risk profile.

Safeguard Your Colorectal Health with Colorectal Practice

Choosing between a FIT kit and a colonoscopy depends on a patient’s individual risk profile, presenting symptoms, and overall screening goals. FIT kits are typically used as a first-line screening tool for average-risk individuals, whereas colonoscopy is recommended when a more comprehensive or diagnostic evaluation is needed. Recognising the distinct role of each test helps guide appropriate screening decisions and ensures a clear, evidence-based screening pathway.

At Colorectal Practice, personalised care is focused on patients who require colonoscopy as part of colorectal assessment or surveillance. If you have been advised to undergo a colonoscopy or are considering whether it is the appropriate next step, a consultation can help determine how it fits into your screening or follow-up plan, with decisions guided by clinical findings, risk profile, and recommended guidelines. Schedule a consultation with us today.

About Our Colonoscopy Specialists

Our team of colorectal surgeons, led by Dr Dennis Koh, provides comprehensive care for patients undergoing colonoscopy. With over 60 years of combined experience, we are highly skilled in performing advanced diagnostic and therapeutic colonoscopies in Singapore. Each procedure is tailored to ensure patient comfort, accurate results, and timely follow-up care.