How bowel screening works
It's a simple at-home test that takes just a few minutes. No appointment needed. Here's what to expect, step by step.
Step by step
The National Bowel Screening Programme uses the faecal immunochemical test (FIT) to detect tiny amounts of blood in your poo. Here's how it works from start to finish.
Receive your kit
If you're aged 58 to 74 and enrolled with a GP, you'll receive a test kit in the post. It contains everything you need: a collection tube, a small stick for sampling, and a prepaid return envelope.
Collect your sample
Using the stick provided, you scrape a small sample from the surface of your poo and place it in the collection tube. It's quick, clean, and done in the privacy of your own bathroom. The kit comes with clear, illustrated instructions.
Tips for collecting your sample
- You only need a tiny amount – about the size of a grain of rice
- Place some toilet paper in the bowl first so the sample doesn't fall into the water
- Scrape the stick across the surface of the poo in several places
- Replace the cap tightly on the tube and shake gently
- Write the date you collected the sample on the tube label
- Post it back as soon as possible, ideally the same day
Post it back
Place the collection tube in the prepaid envelope provided and pop it in any postbox. There's no cost to you. Try to post it on the same day you collect the sample, and avoid posting on a Friday or before a public holiday so it doesn't sit in the mail system over a weekend.
Get your results
You'll receive your results by letter within a few weeks. Your GP will also be notified. Most people receive a clear (negative) result, which means no blood was detected.
Follow-up if needed
If blood is detected (a positive result), you'll be referred for a free colonoscopy to find out what's causing it. A positive result does not mean you have cancer – there are many other explanations.
The FIT test
FIT stands for faecal immunochemical test. It's the type of test used in the National Bowel Screening Programme and in screening programmes around the world.
What it detects
The FIT test looks for tiny amounts of blood in your poo that you can't see with the naked eye (called occult blood). Blood can be a sign of polyps or cancer in the bowel, but it can also be caused by other common conditions like haemorrhoids.
How accurate is it?
FIT is good at picking up bowel cancers and large polyps, but no test is perfect. It can sometimes miss cancers (false negative) or flag something that turns out not to be cancer (false positive). That's why screening is repeated every two years.
Can I request a FIT test outside the screening programme?
Yes. If you're outside the screening age range or have symptoms, your GP can order a FIT test at any time. It may not be free in this case, but it's a straightforward and inexpensive test. Talk to your GP if you think you should be tested.
What a positive result means
Getting a positive result can feel frightening, but it's important to know that a positive screening result usually does not mean cancer.
Of every 100 people who receive a positive FIT result:
- About 4 to 8 will be found to have bowel cancer
- About 30 to 40 will be found to have polyps (which can be removed to prevent future cancer)
- The remaining 50 to 60 will have a clear colonoscopy or another explanation for the blood (such as haemorrhoids)
A positive result simply means blood was found in your sample, and the next step is a colonoscopy to find out why. Even if polyps are found, removing them is a preventative measure – it stops them from potentially becoming cancer in the future.
Colonoscopy follow-up
If your screening result is positive, you'll be offered a free colonoscopy. This is the best way to get a clear picture of what's happening inside your bowel.
What is a colonoscopy?
A colonoscopy is a procedure where a thin, flexible tube with a camera on the end is gently passed into your bowel through your bottom. It allows the specialist to see the entire lining of your bowel and look for anything unusual, such as polyps or areas of inflammation.
What to expect
Before the procedure, you'll need to follow a special diet and drink a bowel-cleansing preparation (most people say this is the hardest part). On the day, you'll be given a sedative to keep you comfortable. The procedure itself takes about 20 to 30 minutes. Most people go home the same day.
If polyps are found
If the specialist finds polyps during the colonoscopy, they can usually remove them there and then. This is painless and is a preventative measure – most polyps are benign (not cancer), but some can develop into cancer over time if left untreated. You'll be given a follow-up plan afterwards.
What if I'm nervous about having a colonoscopy?
It's completely normal to feel anxious. Here are some things that might help:
- You'll be sedated during the procedure, so you won't feel pain – many people don't remember it afterwards
- The medical team does these procedures every day and will look after you
- You can bring a support person with you to the hospital
- Our nurse support line (0800 226 968) can talk you through what to expect and answer any questions
- Knowing the result – whatever it is – puts you in a better position to act
Next steps
Learn more about eligibility, or explore our information about bowel cancer.
Have symptoms? Don't wait for screening
Screening is for people without symptoms. If you've noticed changes, see your GP now. Early detection saves lives.