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Bowel FIT testing: what it checks and when symptoms need a GP
Separate screening, private home testing and investigation of symptoms, with a clear route for medical help.
By SHIFT Some Timber · Sources checked . General information, not an individual assessment. This guide has not been reviewed by a clinician.
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The short answer
FIT looks for blood in a poo sample. It is used in bowel screening and can also form part of investigating symptoms. A positive result does not by itself diagnose cancer, and a negative result does not rule it out. Speak to a GP about bowel symptoms rather than waiting for a home kit.
What FIT measures
FIT means faecal immunochemical test. It checks for blood that may not be visible. A finding of blood needs the appropriate explanation and follow-up; there can be causes other than cancer. The test is one step in a pathway, not a complete look inside the bowel or a general cancer check.
Screening and symptoms are different routes
NHS screening aims to find problems before symptoms. Invitations and arrangements depend on the national programme. A shop-bought test does not enrol you in that programme or automatically arrange its follow-up. If symptoms develop, discuss them with a GP even if a previous screening or home result was reassuring.
Make the important call
Ask a GP about blood in poo, a continuing change in bowel habit or other concerning bowel symptoms. NHS advice is to seek urgent GP help or NHS 111 for black or dark red poo or bloody diarrhoea. For non-stop bleeding or a large amount of blood or large clots, call 999 or go to A&E.
Check the follow-up before purchasing
Ask whether the particular product is read at home or processed by a laboratory, what its result categories mean and who will explain them. Find out how an unclear result is handled. A private result should not leave you guessing whether someone has arranged further assessment; ask directly who is responsible and what you need to do.
Prepare a useful description
Write down when symptoms started, what changed, any medicines and relevant family history to discuss with the GP. Bring the result and leaflet if you have already used a kit. You do not need to prove that something is wrong before asking for help. Ask Timber can explain FIT in general; it cannot rule out bowel cancer or decide what your own result means.
Sources and scope
Source checking is separate from clinical review. Linked guidance may change. Product instructions and service availability must be checked on the current product or provider page.
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