Questions about the stool FIT test · Patient Guide
Negative FIT Test but Still Have Symptoms?
A negative FIT is good news, but it is not the end of the story if your symptoms are still there. Here is what it does and does not rule out.
Written and medically reviewed by Mr Trif Papettas FRCS, Consultant Colorectal and General Surgeon and JAG dual-accredited endoscopist, Nuffield Health Warwickshire Hospital, Leamington Spa. Last reviewed .
Key points
- A negative FIT (below 10 µg/g) makes bowel cancer much less likely, but around 10 to 15% of people with bowel cancer who see their GP with symptoms have a negative FIT.
- FIT only looks for blood. Coeliac disease, inflammatory bowel disease and many other causes of symptoms need different tests.
- National guidance says persistent symptoms after a negative FIT should be reviewed, and your GP can still refer you.
- Some problems need assessing whatever the FIT shows, including a lump in the abdomen or back passage, iron-deficiency anaemia and ongoing visible bleeding.
- A normal bowel screening result does not cover new symptoms.
What does a negative FIT actually tell me?
A negative FIT means little or no blood was found in that one stool sample. It makes bowel cancer much less likely at that point in time, but it does not rule it out, and it says nothing about many other causes of bowel symptoms.
For a FIT your GP requested because of symptoms, negative usually means a result below 10 µg/g, the NICE cut-off for urgent referral (see what your FIT number means). FIT is very good at sorting people into higher and lower risk, which is why it is so widely used. But the joint guideline from the Association of Coloproctology of Great Britain and Ireland and the British Society of Gastroenterology notes that around 10 to 15% of people with bowel cancer who see their GP with symptoms have a negative FIT. That is a small minority, but it is not zero.
Why can a FIT miss something?
- Bleeding comes and goes. Polyps and cancers often bleed on and off, and one sample captures one moment.
- Some growths bleed very little. Smaller polyps in particular may not bleed enough to register.
- FIT only measures blood. Conditions that cause symptoms without bleeding, such as coeliac disease, irritable bowel syndrome, bile acid diarrhoea and some inflammatory bowel disease, will not show up.
- Sample problems. Haemoglobin breaks down over time, so a sample that was delayed or kept warm can read lower than it should.
Which symptoms still need assessing after a negative FIT?
Symptoms that carry on or get worse, and certain warning signs, need review whatever your FIT result.
Ask to be reviewed, whatever your FIT result, if you have:
- Symptoms that carry on, come back or get worse, such as a change in bowel habit lasting more than a few weeks
- Iron-deficiency anaemia on a blood test
- A lump in your abdomen or back passage, or a sore or ulcer around the anus
- Weight loss you cannot explain
- Visible bleeding that keeps happening
- Diarrhoea that wakes you at night
NICE is clear that a negative FIT should not delay referral when there is strong clinical concern, and that GPs can refer people without a positive FIT if they think it is needed. Some findings, such as a rectal mass, an unexplained anal mass or anal ulceration, need referral without a FIT at all.
A family history of bowel cancer does not change how a FIT is read, but it may mean you should be offered colonoscopy surveillance. Ask your GP about this separately.
What does “safety netting” mean after a negative FIT?
Safety netting is the plan your GP puts in place so that you are not lost to follow-up after a negative test.
NICE says safety netting should be in place for everyone with a FIT below 10 µg/g, and for anyone who did not return a sample. It should include:
- An agreed time to review your symptoms, often a few weeks
- Clear advice on which changes should bring you back sooner
- A route to referral if symptoms persist. The ACPGBI/BSG guideline recommends that people with persistent symptoms after a negative FIT are still referred for further investigation
- Further tests where they would help (see below)
If you were not given a review plan, it is reasonable to ask for one.
Should I repeat the FIT test?
Sometimes, but a repeat test is not routine, and it never cancels out an earlier positive result.
Scottish guidance suggests considering a second FIT after about six weeks for people who still have symptoms after a negative first result, and there is some evidence that two tests pick up more than one. The ACPGBI/BSG guideline does not currently recommend routine repeat testing because more research is needed, and NICE also lists two-sample FIT as an area for further research.
A negative second FIT does not cancel out a positive first one. See positive FIT: what happens next.
Which other tests might help after a negative FIT?
| Test | What it looks for | When it is useful |
|---|---|---|
| Full blood count and ferritin | Anaemia and low iron stores | Tiredness, breathlessness, or any suspicion of slow blood loss |
| Coeliac blood test | Coeliac disease | Diarrhoea, bloating, weight loss or anaemia |
| Faecal calprotectin | Bowel inflammation, such as Crohn’s disease or ulcerative colitis | Ongoing diarrhoea, particularly in younger adults |
| Colonoscopy | A direct view of the whole large bowel, with biopsies and polyp removal | Persistent symptoms, anaemia, or when other tests point to the colon |
| CT colonography | A CT scan designed to show the bowel lining | When colonoscopy is not suitable |
| CT scan of the abdomen | The bowel and the organs around it | Weight loss, a lump, or pain that needs wider assessment |
| Gastroscopy | The gullet, stomach and duodenum | Iron-deficiency anaemia, indigestion or swallowing problems; FIT detects bleeding from this area poorly |
More detail: iron-deficiency anaemia investigations, change in bowel habit and IBS or something serious?
Can I get a specialist opinion if my FIT is negative?
Yes. A consultation with a colorectal specialist can decide which test, if any, your symptoms need.
Mr Papettas is a JAG dual-accredited endoscopist, so when both the upper and lower bowel need examining, gastroscopy and colonoscopy can be done in the same visit. Self-referrals are welcome, and tests can usually be arranged within days at Nuffield Health Warwickshire Hospital, Leamington Spa, for patients across Warwickshire and Coventry.
Frequently asked questions
Does a negative FIT mean I don’t have bowel cancer?
It makes bowel cancer much less likely at the time of the test, but it does not rule it out. Around 10 to 15% of people with bowel cancer who see their GP with symptoms have a negative FIT, so symptoms that persist or get worse still need review.
How long should I wait after a negative FIT before going back to my GP?
There is no fixed rule. Your GP should agree a review time with you, often a few weeks. Go back sooner if your symptoms get worse or you notice weight loss, a lump, ongoing bleeding or anything else that worries you.
Can I have a colonoscopy if my FIT is negative?
Yes. A negative FIT does not stop you having a colonoscopy if it is clinically needed. Your GP can still refer you if there is concern, and a private consultation can also assess whether colonoscopy is appropriate.
My FIT was negative but I have iron-deficiency anaemia. What should happen?
Iron-deficiency anaemia needs its cause investigated whatever the FIT result. This often means both a gastroscopy and a colonoscopy, because FIT detects blood loss from the stomach and upper bowel poorly.
I had a normal bowel screening result. Do I still need a FIT for my symptoms?
Yes. Screening is designed for people without symptoms. NICE says a FIT should still be offered to people with symptoms even if they have had a negative screening FIT.
Could my symptoms just be IBS?
Possibly. Irritable bowel syndrome is common, but it should be diagnosed once other causes have been sensibly excluded, particularly if you are over 50 or have warning features such as weight loss, anaemia or bleeding.
Sources
- NICE HTG690 (formerly DG56): Quantitative faecal immunochemical testing to guide colorectal cancer pathway referral in primary care
- Monahan KJ et al. Faecal immunochemical testing (FIT) in patients with signs or symptoms of suspected colorectal cancer: a joint ACPGBI/BSG guideline. Gut, 2022
- British Journal of General Practice (2023): the ACPGBI/BSG FIT guideline and what it means for primary care
This page is general information, not a diagnosis. It was written and medically reviewed by Mr Trif Papettas FRCS on 26 October 2026 against current NICE, NHS England and British Society of Gastroenterology guidance. Next review due October 2027, or sooner if that guidance changes. If you have new or worsening symptoms, speak to your GP or book a consultation. If you have heavy bleeding, black stools, severe abdominal pain or feel faint, call 999 or go to A&E.
Related reading
Negative FIT but symptoms not settling?
Mr Trif Papettas FRCS is a Consultant Colorectal and General Surgeon at Nuffield Health Warwickshire Hospital, Leamington Spa, and a JAG dual-accredited endoscopist. A consultation settles which investigation, if any, your symptoms need, and tests can usually be arranged within days.
Self-referrals welcome · No GP letter required · Self-pay and insured patients seen at Nuffield Health Warwickshire Hospital, Leamington Spa CV32 6RW · Serving Leamington Spa, Warwick, Kenilworth, Stratford-upon-Avon and Coventry