Positive FIT Test: What It Means, Cancer Risk and Next Steps in the UK
A positive FIT test means blood has been detected in your stool sample. In the UK, a positive FIT test does not necessarily mean bowel cancer, but it does mean that further assessment is usually recommended, often with colonoscopy.
This page explains what a positive FIT test means, how often cancer is found, what happens next, and when specialist review is advisable. If you have had a positive bowel screening test, this guide will help you understand your results and the appropriate next steps.
What Does a Positive FIT Result Mean?
A positive FIT result means that the laboratory has detected blood in the stool above the threshold used to trigger further investigation. The test does not identify the cause of the bleeding, only that blood is present.
Common causes of a positive FIT test include:
- Haemorrhoids (piles)
- Benign bowel polyps
- Diverticular disease
Less common but important causes include:
- Advanced pre-cancerous polyps
- Colorectal cancer
How Often Is Cancer Found After a Positive FIT Test?
Large UK and international studies provide important context:
- Colorectal cancer: approximately 3–10%
- Advanced pre-cancerous polyps: approximately 20–40%
- Other causes: account for the remainder
These figures highlight that while cancer is not the most common outcome, a positive FIT test identifies a group of patients who benefit from timely bowel assessment to exclude significant pathology.
Positive FIT Test in the UK: What Happens Next?
In the UK, FIT is used both in the bowel cancer screening programme and in the assessment of lower gastrointestinal symptoms. A positive FIT test usually means blood has been detected above the laboratory threshold used to trigger further assessment, and many patients are then referred for bowel investigation.
FIT detects blood rather than the underlying cause. Some bowel conditions bleed intermittently and may not cause symptoms in early stages. For this reason, guidelines from the National Institute for Health and Care Excellence (NICE) and the British Society of Gastroenterology (BSG) recommend that a positive FIT is usually followed by further assessment, often including colonoscopy.
Does a Positive FIT Test Mean Bowel Cancer?
No. A positive FIT test does not necessarily mean bowel cancer. Common non-cancer causes include haemorrhoids, benign polyps, and diverticular disease. However, colorectal cancer and advanced polyps still need to be excluded through appropriate investigation.
Do I Need a Colonoscopy After a Positive FIT Test?
Many patients do. BSG guidance states that FIT helps identify symptomatic patients who need colorectal investigation with the highest priority, and colonoscopy is commonly used to diagnose the cause and remove polyps if found.
A colonoscopy is commonly recommended because it:
- Examines the lining of the bowel directly
- Allows biopsies to be taken if needed
- Enables removal of polyps during the procedure
In some cases, depending on your age, fitness, and the clinical picture, your specialist may also consider additional endoscopy and digestive investigations as part of a comprehensive assessment.
Is a Positive FIT Test Urgent?
A positive FIT is typically managed on an urgent referral pathway in the NHS. The timing of further assessment may vary depending on local services, clinical priority, and individual circumstances. If you are unsure about next steps, discussing your results with a healthcare professional is advisable.
What Symptoms Should You Be Aware Of?
As a consultant gastroenterologist, I recommend seeking prompt medical advice if you experience:
- Persistent change in bowel habit
- Blood in stools
- Unexplained weight loss
- Iron deficiency anaemia
- Ongoing abdominal pain
Patients with these symptoms may benefit from urgent gastroenterology assessment.
Private Assessment Options
Some patients choose to explore private assessment to obtain a faster diagnosis and clarity on next steps. If considering this, it is important that care is provided by an appropriately qualified consultant specialist, the risks and benefits are clearly explained, and decisions are made based on individual clinical need.
If you would like prompt review, you can book a private gastroenterology appointment in Oxford, Banbury, or Aylesbury. Dr Udit Mittal is an NHS Consultant Gastroenterologist at Oxford University Hospitals and an accredited colonoscopist for the National Bowel Cancer Screening Programme, providing private consultations and colonoscopy across Oxfordshire and Buckinghamshire.
Key Points
- A positive FIT test does not mean cancer, but requires assessment
- It identifies people who may benefit from further investigation
- Colonoscopy is commonly recommended to clarify the cause
- Early identification of bowel conditions can improve outcomes
Frequently Asked Questions
Can haemorrhoids cause a positive FIT test?
Yes. Haemorrhoids can bleed and may cause a positive FIT test, but further assessment may still be needed to rule out other causes.
Does a positive FIT test mean cancer?
No. A positive FIT test means blood was detected in the stool, not that bowel cancer is definitely present. Colonoscopy is often recommended to find the cause.
Should I repeat the FIT test?
Usually no. After a positive FIT test, repeating the test is generally less helpful than proper bowel assessment.
If I feel well, do I still need further tests?
Yes. Some bowel conditions, including early cancer, may not cause symptoms.
Can the FIT test be repeated instead of having a colonoscopy?
In most cases, repeating FIT is not advised after a positive result. Further investigation is usually recommended.
How urgent is a positive FIT test?
In the UK, a positive FIT test is commonly managed through an urgent colorectal assessment pathway, although timing varies by local service and clinical context.