A stool test (FIT) is a good screening test for people at average risk, but it is not the same as a colonoscopy. Here is how to decide.
Patients often ask whether a stool test is enough. For many people at average risk, it is a reasonable choice. But the two tests do different jobs.
What a stool test does
The faecal immunochemical test (FIT) looks for tiny amounts of blood in a stool sample. It is easy, done at home, and repeated every year. A positive result does not mean cancer, but it does mean a colonoscopy is needed.
Its limitation is that many polyps do not bleed, especially small and flat ones. A negative FIT lowers the chance of cancer but cannot show that the bowel is free of polyps.
What a colonoscopy does
A colonoscopy looks at the whole colon and removes polyps in the same session, before they can turn into cancer. If it is complete and normal, it usually does not need repeating for 10 years.
Which is right for you
- Average risk, no symptoms: either a yearly FIT or a colonoscopy every 10 years is reasonable. The best test is the one you will actually do.
- A close relative with colorectal cancer, or polyps removed before: colonoscopy is advised.
- Symptoms such as bleeding, a change in bowel habit, weight loss or anaemia: see a doctor; a stool test is not the right test.
More detail is in the colorectal cancer screening guide.
General information only. Reviewed by Dr Chia Chung King, 2026-11-07. Book a consultation.