What should you know about a FIT food sensitivity test?

The abbreviation FIT can cause confusion because it refers to a faecal immunochemical test, not a food intolerance or food sensitivity panel.

A FIT looks for small amounts of blood that are not visible in stool. Blood can have several causes, including haemorrhoids, bowel inflammation, polyps or cancer. A result showing blood does not by itself identify the cause, and a result without detected blood does not explain ongoing bowel symptoms.

Food sensitivity testing is a separate topic. Symptoms after eating may relate to an intolerance, allergy, coeliac disease or another digestive problem. The right assessment depends on the food, timing, symptoms and examination findings. Home tests that advertise broad food sensitivity panels may not answer the clinical question you have.

Follow the collection instructions from your clinic or screening programme. Use the supplied container, avoid contaminating the sample, and return it as directed. Tell the clinician about visible blood, bowel habit changes, abdominal discomfort, weight loss, medicines and any family history of bowel cancer or bowel disease.

If your concern is a reaction to food, keep a brief record of what you ate, when symptoms began, and what happened. Do not remove many foods for a long period without guidance, because this can make meals unbalanced and may make diagnosis harder.

Arrange medical advice promptly for blood in the stool, black or tarry stool, a persistent change in bowel habit, unexplained weight loss, ongoing abdominal pain, or unusual tiredness. Seek urgent help for heavy bleeding, fainting, severe abdominal pain, or signs of dehydration.

A positive FIT result needs follow-up arranged by a clinician; it is not a diagnosis. Ask how and when you will receive the result and what further assessment is recommended.

Ask: Is this FIT being offered as routine screening or because of my symptoms? How should I collect and return the sample? What could affect the result? If I have food-related symptoms, which evaluation is appropriate, and should I see an allergy or digestive specialist?