Food Allergy & Intolerance Tests: What Works and What Doesn't
Written by Jordan Morley · Reviewed against NHS guidance on food allergy and food intolerance · Last updated 28 October 2026
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If certain foods keep causing bloating, discomfort or a reaction, it is natural to want a test. The honest picture is more mixed than the adverts: some tests are reliable and are done through the NHS, while many of the home kits sold online are not supported by good evidence. This guide sets out what works, what doesn't, and the practical kit that helps once you know.
The testing routes compared
| Route | What it can tell you | How reliable? | Where |
|---|---|---|---|
| Food and symptom diary | Whether symptoms follow particular foods | Useful for spotting patterns; the usual first step | At home, free |
| Elimination and reintroduction | Which food triggers symptoms | Reliable when done properly; best guided by a GP or dietitian | GP or dietitian |
| Skin-prick and blood tests for allergy (IgE) | Whether you are allergic to a food | The recognised route; results must be read alongside your history | GP referral to an allergy service |
| Coeliac blood test | Coeliac disease | Reliable only if you are still eating gluten when tested, so do not cut it out beforehand | GP |
| Breath test for lactose intolerance | Whether lactose is the trigger | Used in specialist settings | Specialist referral |
| Home IgG 'food sensitivity' and hair tests | Marketed as finding intolerances | The NHS says there is no good evidence that they work | Sold online |
Our picks
Food and symptom diary
Before any test, a simple log of what you ate and how you felt is still the most reliable way to spot a pattern, and it gives your GP or dietitian something concrete to work from. A notebook works as well as an app.
Check Price →See your GP about allergy and intolerance testing
If you may be allergic, your GP can refer you for skin-prick or blood testing. If you suspect an intolerance, they or a dietitian can guide a safe elimination and reintroduction diet. This route costs nothing at the point of use and is the one that leads to a reliable answer.
HealthLabs.com panel (US only)
A US service that lets you order lab tests online without a doctor's referral. It is included for US visitors; UK readers should start with their GP. Be aware that the NHS does not recommend commercial IgG food-sensitivity tests, so treat any result as a prompt for a conversation with a clinician, not a diagnosis.
Check HealthLabs.com (US) →Lactase enzyme tablets
If lactose has been identified as the trigger, lactase tablets taken with dairy let some people keep milk and cheese in their diet. Check with a pharmacist, and see a GP first if symptoms are severe or new.
Check Price →Glass meal-prep containers
Once you know what to avoid, batch-cooking your own meals makes it far easier to control what goes in. Cool and chill batch-cooked food promptly; see our container guide and leftovers times.
Check Price →Common questions
What is the difference between a food allergy and a food intolerance?
An allergy involves the immune system and can cause reactions such as hives, swelling or breathing difficulty, sometimes within minutes. An intolerance, such as lactose intolerance, is not an immune reaction and usually causes digestive symptoms such as bloating or diarrhoea, often hours later.
Do the NHS recommend home food intolerance tests?
No. The NHS says that many of the food intolerance tests sold online, including IgG blood tests and hair analysis, are not supported by good evidence. If you think a food is causing problems, start with a diary and speak to your GP.
Should I cut out gluten before a coeliac test?
No. Coeliac blood tests are only reliable if you are still eating gluten, so keep it in your diet until you have been tested.
Can food allergies be dangerous?
Yes. Severe allergic reactions (anaphylaxis) are medical emergencies. Call 999 if someone has trouble breathing or swelling of the face or throat after eating.
Related guides
Based on NHS guidance on food allergy and food intolerance. We do not test or rate individual products, quote prices or publish user reviews. Affiliate links do not influence what we include.
General information only, not medical advice: see the medical disclaimer. Feeling unwell after eating something? Contact NHS 111 or your GP.