Using FIT to manage people with symptoms in primary care
In primary and secondary care, the Faecal Immunochemical Test (FIT) is used to guide the management of people with colorectal symptoms.
The threshold for a positive symptomatic test is lower than for screening, at 10 µg Hb/g faeces in England, Wales and Northern Ireland and 20 µg Hb/g in Scotland. See our page on the differences between FIT in bowel cancer screening and for people with symptoms.
When should a FIT be used?
FIT is not required for all colorectal symptom presentations. People who present with a rectal or anal mass or anal ulceration should be referred urgently on a lower gastrointestinal (GI) pathway without a FIT.
For other colorectal symptoms, FIT should be used to aid your decision to refer into secondary care.
Each nation has different guidelines outlining criteria for when you should offer a FIT. Make sure you’re aware of your local pathways and open the relevant guidance below for more information:
BSG/ACPGBI UK-wide guidance (2022)
NICE NG12 guidance (2023)
Scottish Referral Guidelines (2025)
NICaN Lower GI guidance
Wales Lower GI Symptomatic FIT National Optimal Pathway (2023)
Unless FIT is only available in secondary care in your local pathway, primary care is responsible for requesting the test and acting on the results.
If a kit is spoiled or rejected, primary care are responsible for ordering an additional kit via local processes.
Lynch syndrome
People with Lynch syndrome have an increased risk of developing bowel and other cancers. Surveillance colonoscopies are offered every two years to support early detection for people with Lynch syndrome, but primary care should be aware of the risk and make sure to investigate people with symptoms should they present. If you’re clinically concerned, consider an urgent referral.
What to do when someone has a positive FIT result
People with a positive FIT should be referred along an urgent cancer pathway for follow-on investigation. In most local pathways, a FIT result is required alongside a referral to inform secondary care prioritisation.
It is important to inform patients why they are being referred along an urgent cancer pathway. Where appropriate, you can share that most people with a positive FIT result will not go on to be diagnosed with bowel cancer [1].
What to do when someone has a negative FIT result
A negative FIT result can provide reassurance as the majority of people (~99%) with a negative FIT will not have bowel cancer [1]. However, GPs should still be alert to the risk of bowel cancer as around 10% of people diagnosed with colorectal cancer will have had a negative FIT result [1].
People should not be discharged from the pathway based on a FIT result alone. Use your clinical judgement to assess whether people with a negative FIT result should still be referred.
Some signs and symptoms of suspected colorectal cancer overlap with other cancers (for example gynaecological or upper gastrointestinal cancers). If you suspect other cancers, consider investigation and referral through the most appropriate pathway.
Safety net your patients until symptoms are explained or resolved. Encourage your patients to follow-up if their symptoms persist, worsen or change after a negative FIT result. Go to our safety netting webpage for top tips to support your practice.
Repeating a FIT
If a patient with colorectal symptoms has a positive FIT result, there’s no need to repeat a FIT as this warrants referral to secondary care.
There’s emerging evidence that if someone has two negative FIT results, their chance of being diagnosed with colorectal cancer are lower than in somebody with a single negative FIT [2,3,4]. If repeat FIT testing is recommended, it should be balanced with the capacity needed for increased investigation use [5].
Follow local and national guidelines when considering whether to offer a repeat FIT. Currently, repeat FIT is only recommended in Scotland for people who’ve presented with iron deficiency anaemia or where there’s ongoing clinical concern [6]
What do when someone does not return a FIT
Evidence suggests that some groups of people are less likely to accept, complete and return a FIT. These include men, those aged under 65 years, people from ethnic minority groups and people from more deprived areas [7].
Understanding these patient groups and encouraging them to complete and return their tests is key to reducing inequalities in FIT uptake. Find out how you can support symptomatic FIT completion and access our patient resources on our symptomatic FIT page.
Use safety netting tools to alert you or your practice if somebody hasn’t returned a FIT within a certain timeframe. If you have clinical concern about cancer, despite somebody declining to return a FIT, you should still consider referral.
A study found no significant difference in bowel cancer prevalence between people who completed a FIT and people who didn’t return their test before secondary care referral [9].
Research and future optimisation of FIT
There’s significant interest in using FIT results combined with patient characteristics, blood test results or other innovative tests to assess colorectal cancer risk more accurately. For example, the COLOFIT research programme has developed an algorithm that detects a similar number of cancers as current practice, while reducing the number people that would be referred for a colonoscopy [10]. Next steps include understanding the impact of implementing this algorithm on patient outcomes and investigating how to implement the tool optimally and equitably.
Evidence gaps remain around the reasons why certain groups engage less with FIT and interventions that support uptake. Further research should support the development of effective interventions to address barriers and support equal uptake of the test.
Our Test Evidence Transition programme aims to accelerate the effective adoption of service innovations whilst working to improve equal access to proven interventions. Phase 2 of the programme is seeking to optimise both the screening and symptomatic pathways to improve the early detection and diagnosis of colorectal cancers.
Get in touch with us to find out more about FIT optimisation activity:
References
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Harnan, S. et al. Faecal immunochemical tests for patients with symptoms suggestive of colorectal cancer: An updated systematic review and multiple‐threshold meta‐analysis of diagnostic test accuracy studies. Colorectal Disease, 2024
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Gerrard et al. Double faecal immunochemical testing in patients with symptoms suspicious of colorectal cancer. 2023.
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Johnstone M et al. Prevalence of repeat faecal immunochemical testing in symptomatic patients attending primary care. Colorectal Disease. 2022.
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Gerrard, A.D. et al. Repeat Faecal Immunochemical Testing for Colorectal Cancer Detection in Symptomatic and Screening Patients: A Systematic Review and Meta-Analysis. Cancers, 2024.
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Farkas, N.G. et al. The repeat FIT (RFIT) study: Does repeating faecal immunochemical tests provide reassurance and improve colorectal cancer detection? Colorectal disease : the official journal of the Association of Coloproctology of Great Britain and Ireland, 2024.
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Quantitative Faecal Immunohistochemical Testing (qFIT) for patients with new lower gastrointestinal symptoms, NHS Scotland, 2024.
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Bailey JA et al. Sociodemographic Variations in the Uptake of Faecal Immunochemical Tests in Primary Care. British Journal of General Practice. 2023
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Sienna Hamer‐Kiwacz, et al., (2024). Barriers and facilitators to faecal immunochemical testing in symptomatic populations: A rapid systematic scoping review and gap analysis. Journal of Evaluation in Clinical Practice. 2024.
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Gerrard, A.D. et al., Colorectal cancer prevalence in faecal immunochemical test non-returners: potential for health inequality in symptomatic referral pathways. BJS Open. 2024
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Crooks, C.J., et al., COLOFIT: Development and Internal-External Validation of Models Using Age, Sex, Faecal Immunochemical and Blood Tests to Optimise Diagnosis of Colorectal Cancer in Symptomatic Patients. Alimentary pharmacology & therapeutics, 2025.