Cancer Screening·22 May 2026·Northwest Health

ColoAlert® vs the NHS FIT test: what's the difference?

Both are simple at-home bowel cancer tests, but they look for different things. Here's how ColoAlert® and the NHS FIT test compare — and where each one fits.

Bowel cancer is one of the most treatable cancers when caught early, and at-home testing makes screening far easier. Two tests come up most often: the NHS FIT test and ColoAlert®. They're not the same.

What the FIT test looks for

The NHS Faecal Immunochemical Test (FIT) detects tiny, hidden amounts of blood in a stool sample. It's free, valuable, and the backbone of the NHS bowel screening programme. Its limitation: early bowel cancers and pre-cancerous growths don't always bleed, so they can be missed.

What ColoAlert® adds

ColoAlert® is a next-generation stool DNA test. As well as checking for hidden blood, it looks for tumour DNA — genetic markers shed by abnormal cells. Because it doesn't rely on bleeding, it can pick up changes a blood-only test might miss.

  • ColoAlert® detects around 85% of colorectal cancers, compared with roughly 65–70% for FIT alone.
  • It's also better at flagging advanced adenomas (pre-cancerous growths).

Which test is right for me?

FIT is an excellent, free first-line test and is right for most people in the NHS screening age range. You might consider ColoAlert® if you:

  • Want a more sensitive option for added reassurance
  • Have a family history of bowel cancer
  • Had a negative FIT but still have concerns
  • Are 40–60 and want to screen before NHS screening begins
  • Would prefer to avoid, or aren't ready for, a colonoscopy

It's not for anyone with current red-flag symptoms — bleeding, a persistent change in bowel habit, or unexplained weight loss should be seen by a doctor promptly, not screened at home.

What happens if a test is positive?

Neither test diagnoses cancer — they flag who needs a closer look. A positive result usually means the next step is a colonoscopy. With ColoAlert® through us, a GP reviews every result and arranges any referral.

An important caveat

No screening test is perfect. A normal result doesn't completely rule out cancer, and screening is not a substitute for seeing a doctor about symptoms. That's exactly why a GP reviews your result and puts it in context.

Learn more about ColoAlert® bowel cancer screening →

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