Food Intolerance Test UK (2026): What Actually Works (and What Doesn't)
Information, not medical advice
If you suspect a serious food reaction (especially anaphylaxis or persistent GI symptoms), see your GP. Full disclaimer.
The 60-second answer
If you only read one box
- Food allergy ≠ food intolerance. Allergies are IgE-mediated and testable. Intolerances are mostly not.
- IgG home tests (Yorktest, Lorisian, Cambridge Nutritional Sciences consumer kits) are not validated. The NHS, NICE, BSACI and EAACI all say they don't diagnose food intolerance. A positive IgG result mostly means you've eaten the food.
- Gold standard for intolerance: a structured elimination-and-reintroduction diet supervised by an HCPC-registered dietitian. Free on the NHS via GP referral.
- What is worth blood-testing: coeliac antibody (rule out coeliac before going gluten-free), ferritin/B12/vitamin D (rule out malabsorption), and specific IgE if you suspect true allergy.
Allergy vs intolerance — the distinction that decides everything
Most of the confusion in this market comes from collapsing two completely different things into one buzzword.
Food allergy (IgE-mediated)
- Reaction within minutes to two hours.
- Symptoms: hives, swelling, wheezing, vomiting, anaphylaxis.
- Mechanism: specific IgE antibodies binding to mast cells, triggering histamine release.
- Testable: specific IgE blood test, or skin-prick test in an allergy clinic. Validated. NHS uses this.
Food intolerance (non-IgE)
- Reaction delayed, often hours.
- Symptoms: bloating, gas, cramps, headaches, brain fog, fatigue.
- Mechanism: enzyme deficiency (lactose intolerance = lactase deficiency), pharmacological (caffeine, histamine, sulphites), or non-IgE immune (some FODMAP responses).
- Mostly not blood-testable. Gold standard is an elimination-and-reintroduction diet.
The IgG home-test market sits in a third invented category — "IgG food sensitivity" — which is not a recognised clinical diagnosis.
Why IgG food intolerance tests aren't recommended
The mainstream position is unusually consistent for nutrition science. Here's what each authority actually says.
- NHS — "There's no clear evidence to suggest that food intolerance tests, including those that measure IgG antibodies, work."
- NICE — has not recommended IgG testing for food intolerance in any guideline.
- British Society for Allergy and Clinical Immunology (BSACI) — explicitly recommends against IgG food intolerance testing.
- European Academy of Allergy and Clinical Immunology (EAACI) — position paper concludes IgG testing for food intolerance is "not recommended" and "may lead to unnecessary dietary restriction".
- American Academy of Allergy, Asthma and Immunology (AAAAI) — same position.
The mechanism reason: a measurable IgG response to a food is a normal consequence of eating that food and being exposed to it. It indicates immune tolerance, not pathology. So a "positive" IgG test against eggs, dairy and wheat in someone who eats eggs, dairy and wheat is precisely what the immune system is supposed to do.
The practical reason: every blinded study (Atkinson 2004, Hochwallner 2014, Stapel 2008) has either failed to replicate IgG-guided benefit or shown that any improvement comes from the placebo of removing foods, not from the IgG matching itself.
The actual gold standard: a structured elimination diet
If you have persistent digestive or systemic symptoms you suspect are food-related, this is the validated process.
- See your GP first. Rule out coeliac disease, IBD, thyroid issues and (in the right context) H. pylori. These can mimic "food intolerance" exactly.
- Ask for a dietitian referral (NHS via GP, or self-refer privately — ~£60–£120 per session). An HCPC-registered dietitian will design the elimination phase.
- Elimination phase (2–6 weeks). Remove suspect foods (commonly dairy, gluten, eggs, soy, high-FODMAP foods) under supervision. Log symptoms daily.
- Reintroduction phase. Add one food at a time, every 3–4 days, watching for reproducible symptoms. This is where the actual diagnosis happens.
- Long-term plan. Reintroduce as much as possible — overly restrictive diets cause their own problems (nutrient deficiencies, disordered eating).
The low-FODMAP diet (Monash University protocol) is a particularly well-evidenced elimination framework for irritable bowel syndrome (IBS) symptoms. It is time-limited, structured and reintroduction-led — not a permanent restriction.
Blood tests that are worth doing for digestive symptoms
Three categories make sense.
1. Coeliac antibody — before you go gluten-free
If you're thinking about cutting gluten because it might be the problem, test for coeliac first. Once you're gluten-free, the test (tissue transglutaminase IgA + total IgA) becomes unreliable.
- Coeliac antibody test — what it is and what it doesn't tell you
- Available from Medichecks (~£35–£49) and Forth.
2. Malabsorption screen
Chronic GI symptoms can cause (or be caused by) nutrient deficiencies. A baseline of:
- Full blood count (FBC) and ferritin — iron-deficiency anaemia signal.
- Vitamin B12 and folate — low B12 in pernicious anaemia or chronic malabsorption.
- Vitamin D — universally worth knowing in the UK.
Most postal providers (Medichecks, Thriva, Forth) bundle these into ~£49–£89 panels.
3. Specific IgE — if you suspect true allergy
If you have rapid-onset symptoms after a specific food (hives, swelling, breathing trouble), that is allergy not intolerance, and a specific IgE blood test or referral to an NHS allergy clinic is the right next step. Don't use an IgG panel for this — they measure different things.
UK food intolerance brands — what they sell, what we think
Common UK names in this space: YorkTest, Lorisian, Cambridge Nutritional Sciences (consumer kits, distinct from their clinical lab work), Check My Body Health, and various Amazon-listed white-label kits.
Honest assessment:
- Lab analytics are generally fine (UKAS ISO 15189 in many cases).
- But the clinical interpretation — that IgG against food X means you should avoid food X — is not supported by current evidence.
- Many people report symptom improvement after one of these tests. That is almost certainly the result of removing foods (any restriction tends to help bloating short-term) plus the placebo of "doing something definite", not the specific IgG matching.
We don't recommend any IgG food intolerance product on this site. We do link to coeliac antibody and general health panels because those are validated.
FAQ
Do food intolerance tests work?
IgE allergy testing works. IgG food intolerance testing is not supported by the NHS, NICE, BSACI or EAACI. The validated route for intolerance is an elimination-and-reintroduction diet.
Allergy vs intolerance?
Allergy = fast, IgE-mediated, testable. Intolerance = slow, non-IgE, mostly diagnosed by elimination diet.
What does the NHS say about IgG tests?
The NHS explicitly states there's no clear evidence that IgG food intolerance tests work.
What is the gold standard?
A structured elimination-and-reintroduction diet supervised by an HCPC-registered dietitian.
What blood tests are worth doing?
Coeliac antibody, basic malabsorption screen (FBC, ferritin, B12, folate, vitamin D), and specific IgE if true allergy is suspected.
How much do food intolerance tests cost?
IgG panels: £99–£299 (we don't recommend them). Coeliac antibody: £35–£49. Specific IgE privately: £70–£150 per panel via an allergy clinic.
Related reading
- Private blood tests UK — pillar guide — the complete UK private testing playbook.
- Private coeliac blood test UK — the validated alternative to IgG food panels for gluten symptoms.
- Allergy blood test UK — the IgE vs IgG distinction, and why “food intolerance” panels are advised against by every UK clinical body.
- Coeliac antibody test deep-dive — marker science behind the buyer guide.
- Are home blood tests accurate?
- How to choose a private blood test (UK)
- How to read your blood test results
- Best UK private blood test providers (9 compared)