Food Intolerance Tests: What Works and What Doesn't

Reviewed and written by Dr Zeeshan Afzal, MBBS — Medical Doctor and Medical Content Lead at Welzo. Last updated: August 2026. Next review: August 2027.

Search for a food intolerance test UK and you will be offered dozens of kits within seconds — hair samples, finger-prick blood panels tested against 200 foods, and machines that promise to read your body's "energy". Prices run from around £30 to well over £300. What almost none of them tell you is that the NHS, the British Dietetic Association, NICE and the European Academy of Allergy and Clinical Immunology have all reviewed the same evidence and reached broadly the same conclusion: the most heavily marketed intolerance tests do not do what the marketing says. That does not mean your symptoms are imaginary, or that nothing can be tested. Some tests are genuinely useful and validated. This guide separates the two, explains what to do instead, and shows you the pathway a doctor would actually follow. If you are working through digestive symptoms more broadly, our complete guide to gut health in the UK is the best starting point, and you can browse evidence-based support in the Welzo gut health range and probiotics collection. For targeted options, many readers look at Akkermansia muciniphila, modified citrus pectin powder, Welzo Ultra Purity Berberine and Welzo Ultra Purity TUDCA. It is also worth reading how a gut microbiome test differs from an intolerance test, and what a coeliac test actually measures.

Key takeaways

• IgG and IgG4 food antibody tests — the most common commercial "food intolerance test UK" kits — are not recommended by the NHS, NICE, the BDA or EAACI. A positive IgG result usually reflects that you eat the food, not that you react to it.
• Hair analysis, bioresonance, Vega/electrodermal testing, applied kinesiology and cytotoxic (ALCAT-style) testing have failed under blinded conditions and are not diagnostic.
• Tests that do work: coeliac serology plus biopsy, hydrogen and methane breath testing for lactose malabsorption and SIBO, specific IgE and skin prick testing for true allergy, faecal calprotectin for inflammation, and a structured elimination-and-reintroduction diet.
• A supervised elimination and reintroduction protocol remains the reference standard for identifying genuine food intolerance, and it is free on the NHS via a GP referral to a dietitian.
• Unvalidated tests carry real risk: unnecessary dietary restriction, nutritional gaps, disordered eating patterns, and delayed diagnosis of coeliac disease, IBD or bowel cancer.

Table of contents

• What is a food intolerance — and what isn't
• Why food intolerance testing is so confusing in the UK
• Food intolerance tests that work
• Food intolerance tests that don't work
• Comparison table: validated vs unvalidated tests
• What the evidence really says about IgG testing
• The real risks of relying on an unvalidated test
• Food intolerance test costs in the UK
• The evidence-based pathway, step by step
• Common intolerances and how they are actually diagnosed
• Where supplements and gut support fit in
• Red flags: when to see a GP urgently
• How to read a private test provider's claims
• Frequently asked questions
• References

What is a food intolerance — and what isn't

The single biggest source of confusion in this area is that "food intolerance", "food allergy" and "coeliac disease" are used interchangeably in marketing copy, when they are three biologically distinct things requiring three different tests.

Food intolerance

A food intolerance is a non-immune adverse reaction to a food. The NHS is explicit that a food intolerance is not caused by the immune system overreacting, which is why you cannot have anaphylaxis from an intolerance. The usual mechanisms are enzyme deficiency (as in lactase deficiency), fermentation of poorly absorbed carbohydrates, pharmacological effects of food chemicals, or heightened gut sensitivity. Symptoms tend to be dose-dependent — a splash of milk in tea is fine, a milkshake is not — and typically appear hours after eating.

Food allergy

A food allergy is an IgE-mediated immune reaction. Symptoms appear within minutes to two hours and can include hives, swelling of the lips and throat, wheeze and anaphylaxis. This is a medical emergency and is diagnosed with specific IgE blood tests, skin prick testing and, where needed, a supervised oral food challenge.

Coeliac disease

Coeliac disease is neither an allergy nor an intolerance. It is an autoimmune condition in which gluten triggers immune damage to the small bowel lining. It affects roughly 1 in 100 people in the UK, and many remain undiagnosed. It has a specific, validated diagnostic pathway. Our guide on coeliac disease versus gluten intolerance explains the distinction in detail.

Non-coeliac gluten or wheat sensitivity

A recognised but poorly understood entity, diagnosed only by excluding coeliac disease and wheat allergy first, then demonstrating symptom improvement on withdrawal and recurrence on blinded rechallenge. See our article on gluten intolerance in the UK.

Lactose intolerance is the most common true food intolerance in the UK — and one of the few with a validated diagnostic test. Image: Wikimedia Commons, freely licensed.

Why food intolerance testing is so confusing in the UK

There is a genuine unmet need driving this market. Pooled data from population studies show around 17% of people report a lifetime food hypersensitivity, but only about 2.7% are confirmed by skin prick testing and under 1% by formal food challenge. That is a large gap between how many people feel unwell after eating and how many have a demonstrable, testable reaction.

Into that gap steps a commercial testing industry that is only lightly regulated. Home tests are sold as consumer products rather than as diagnostic medical devices with clinical validation requirements. The result is that a test can be accurate in the narrow laboratory sense — it really does measure the IgG antibody it claims to measure, in an accredited lab — while being clinically meaningless, because the thing it measures does not correspond to the thing you want to know.

This is the distinction that matters most, and it is the one the marketing consistently blurs. "UKAS-accredited laboratory" describes the quality of the measurement. It says nothing about whether the measurement predicts symptoms.

Food intolerance tests that work

Coeliac serology and duodenal biopsy

The validated pathway is a blood test for IgA tissue transglutaminase antibodies (tTG-IgA), with total IgA measured at the same time to exclude IgA deficiency, followed in most adults by referral for duodenal biopsy. Coeliac UK notes that in some cases both adults and children can now be diagnosed on blood tests alone without biopsy, though practice varies across the UK.

The single most important point: you must be eating gluten regularly — at least one gluten-containing meal a day for six weeks — before testing. Going gluten-free first is the commonest reason for a false negative, and it is the commonest mistake people make. Coeliac UK is clear that home testing kits are not a substitute for medical diagnosis.

Villous atrophy in the duodenum — the gut lining damage that defines coeliac disease and that no hair or IgG test can detect. Image: Wikimedia Commons, freely licensed.

Hydrogen and methane breath testing

Breath testing is one of the few genuinely validated tools for carbohydrate intolerance. You drink a measured dose of lactose, fructose or lactulose, then breathe into a collection device at set intervals for two to three hours. If the sugar is not absorbed in the small intestine, colonic bacteria ferment it and produce hydrogen and methane, which cross into the bloodstream and are exhaled.

Breath testing is used for lactose malabsorption, fructose malabsorption and small intestinal bacterial overgrowth. It is not perfect — a proportion of people are non-hydrogen-producers, which is why measuring methane alongside hydrogen improves detection, and breath results do not always track symptoms neatly. But it measures a real physiological process, which places it in an entirely different category from the tests in the next section. Read more in our guides to SIBO testing in the UK and SIBO symptoms and management.

Specific IgE testing and skin prick testing

If your symptoms are rapid-onset — itching, hives, swelling, wheeze within two hours — you may have an allergy rather than an intolerance, and these are the correct tests. They are only interpretable alongside a clinical history: a positive result without matching symptoms indicates sensitisation, not allergy, and should not by itself trigger food avoidance.

Skin prick testing is validated for IgE-mediated food allergy — not for food intolerance. Image: Wikimedia Commons, public domain.

Structured elimination and reintroduction

This is the reference standard, and it is the approach the NHS recommends. A single suspected food is removed completely for two to four weeks while symptoms are tracked, then deliberately reintroduced to see whether symptoms return. If they do, and the pattern repeats, you have functional evidence of intolerance to that food in that quantity.

Done properly it needs three things: a symptom and food diary, complete removal including hidden sources, and — critically — a genuine reintroduction phase. Skipping reintroduction is how people end up on permanently restricted diets based on a coincidence. Track your bowel changes objectively using the Bristol Stool Chart.

The low FODMAP diet with reintroduction

For people with IBS, a dietitian-led low FODMAP diet is the most evidence-supported dietary intervention available. It is a diagnostic process as much as a treatment: a restriction phase, then systematic reintroduction of each FODMAP group to identify personal triggers and thresholds, then long-term personalisation.

It is not a permanent diet, and the restriction phase should not be run indefinitely without supervision — prolonged restriction reduces intake of fermentable fibres your microbiome depends on. See our guides to the low FODMAP diet in the UK, the FODMAP food list and the FODMAP reintroduction phase. Knowing your IBS subtype also shapes which foods matter most.

Faecal calprotectin and baseline bloods

These do not diagnose intolerance, but they answer the question that must come first: is something else going on? Faecal calprotectin distinguishes inflammatory bowel disease from IBS. A full blood count, ferritin, CRP, coeliac serology and thyroid function pick up anaemia, inflammation and thyroid disease that can mimic food-related symptoms. Our guides to calprotectin testing, stool testing in the UK and gut health blood tests explain what each one covers. If you have upper abdominal pain or reflux, an H. pylori test is often appropriate too.

Genetic lactase testing — useful, with limits

Testing for the MCM6/LCT variants associated with lactase persistence tells you whether you are genetically predisposed to adult-type lactase non-persistence. It is reliable for what it measures, but it predicts capacity rather than symptoms: many people with the non-persistence genotype tolerate moderate dairy without difficulty. It is best used alongside a breath test or a structured dairy challenge, not instead of one. See lactose intolerance supplements and management.

Lactose content varies by dairy product, and most people with lactase non-persistence tolerate small doses. Image: Wikimedia Commons, freely licensed.

Food intolerance tests that don't work

IgG and IgG4 food antibody tests

This is the dominant format sold as a "food intolerance test UK" — a finger-prick sample screened against 50 to 200+ foods, returning a colour-coded list of "reactive" items.

The problem is biological, not technical. IgG antibodies to food are a normal, expected response to eating that food. The EAACI Task Force concluded that food-specific IgG4 indicates repeated exposure and immunological tolerance rather than hypersensitivity, and that testing IgG4 to foods is irrelevant to the workup of food allergy or intolerance. The American Academy of Allergy, Asthma and Immunology formally endorsed that position, and the Canadian Society of Allergy and Clinical Immunology issued its own statement against IgG food testing.

In practice this produces predictable artefacts. The foods you eat most — milk, wheat, eggs, yeast — are the ones most likely to flag positive, which is why results so often name staples. And someone who has already cut out a food may test negative for it precisely because they stopped eating it.

The NHS position is unambiguous: some tests you can buy that claim to diagnose food intolerances are not recommended, there is limited evidence they give accurate results, and they may lead you to avoid multiple foods, which can be harmful.

Hair analysis

Hair is keratinised, metabolically inactive protein. It contains no food-specific antibodies, no immune cells and no record of digestive function. There is no plausible mechanism by which a hair sample could report your response to 600 foods. NICE explicitly lists hair analysis among tests that should not be used in diagnosing food allergy.

Bioresonance and Vega/electrodermal testing

These devices claim to detect intolerance by measuring changes in skin electrical resistance while food vials are placed in a circuit. They have been tested rigorously. A double-blind randomised study published in the BMJ in 2001 found that electrodermal testing results did not correlate with skin prick test results, could not distinguish atopic from non-atopic participants, and that no operator performed better than any other. A double-blind, placebo-controlled study in Clinical and Experimental Allergy in 2002 reached the same conclusion, finding no significant difference in skin electrical response between allergens and negative controls.

Applied kinesiology

Muscle-strength testing while holding a food sample. NICE lists applied kinesiology alongside the Vega test and hair analysis as tests that should not be used to diagnose food allergy. Results are highly susceptible to unconscious operator influence and are not reproducible under blinded conditions.

Cytotoxic and leukocyte activation tests (ALCAT-style)

These measure changes in white blood cell size or shape when exposed to food extracts in a test tube. Reproducibility has been poor and the results do not predict symptoms in blinded challenge studies. Reviews of unproven diagnostic tests in food allergy group cytotoxic testing with IgG testing, electrodermal testing and applied kinesiology as unvalidated approaches that risk unnecessary elimination diets.

Iridology, pulse testing and "energy" screening

No plausible mechanism, no validation, no place in diagnosis.

Microbiome tests marketed as intolerance tests

This one needs care, because the underlying science is real. Sequencing your stool microbiome genuinely tells you something about bacterial composition. What it cannot currently do is tell you which foods you are intolerant to — the predictive models are not validated to that standard. A microbiome report suggesting you "avoid" a list of foods is going beyond what the data supports. Our comparison of UK microbiome tests and article on zonulin testing cover what these tests can and cannot show, and is leaky gut real? addresses a related claim.

Comparison table: validated vs unvalidated tests

What the evidence really says about IgG testing

It is worth being straight about the counter-argument, because reputable providers cite real trials.

The most-cited is a 2004 randomised controlled trial in Gut by Atkinson and colleagues, in which 150 IBS outpatients followed either a diet excluding foods to which they had raised IgG antibodies or a sham diet excluding the same number of different foods. The true diet produced a modest but statistically significant reduction in symptom severity compared with sham. A 2011 trial in Nutrition Journal applied the same approach to migraine-like headaches, and a 2025 multicentre randomised sham-controlled trial in Gastroenterology using a novel IBS-specific 18-food IgG assay found participants on the antibody-guided diet were more likely to meet the primary endpoint, while explicitly noting that previous studies had serious methodological limitations and that a larger study is needed to validate the findings.

So the honest position is more nuanced than "IgG is worthless". But three things follow from the evidence as it stands:

• Trial benefit does not equal diagnostic accuracy. Showing that an IgG-guided elimination diet outperforms a sham elimination diet in a trial population is not the same as showing that a positive IgG result means you are intolerant to that food. Some of the benefit may simply come from structured, supervised dietary change.
• The trials used small, defined panels in supervised settings. They did not test 200-food consumer panels interpreted without clinical input, which is what is actually sold.
• Every major professional body has weighed this literature and still advises against routine IgG food testing. That includes EAACI, the AAAAI, the CSACI, NICE, the BDA and the NHS.

If you have already bought an IgG test, the sensible use of the result is as a hypothesis to test — take one or two flagged foods and run a proper elimination and reintroduction on them — rather than as an instruction to remove twenty foods at once.

The real risks of relying on an unvalidated test

Unnecessary restriction and nutritional gaps

A panel returning fifteen "reactive" foods commonly removes dairy, wheat, eggs and yeast simultaneously. That is a meaningful loss of calcium, iodine, B vitamins, iron and fibre, and it is difficult to replace without planning. The NHS warns specifically that these tests may suggest avoiding multiple foods, which can be harmful.

Loss of microbiome diversity

Fewer plant foods means less fermentable fibre, which means less substrate for the bacteria that produce short-chain fatty acids. This is a measurable downside of long-term restriction. See microbiome diversity, short-chain fatty acids and the 30 plants a week target.

Disordered eating

A test-generated list of "bad" foods can entrench food fear and rigid eating. If you notice anxiety around eating, escalating restriction, or distress when a "banned" food is unavoidable, speak to your GP.

Delayed diagnosis

This is the most serious risk. Bloating, altered bowel habit, fatigue and abdominal pain are also the presenting symptoms of coeliac disease, inflammatory bowel disease, and bowel cancer. Months spent on a self-directed elimination diet based on a hair test is time not spent getting a calprotectin, a coeliac screen or a colonoscopy. Read when to see a GP about stomach symptoms and bowel cancer screening in the UK.

Food intolerance test costs in the UK

Prices are indicative and vary by provider and region. The pattern worth noticing is that the tests with the strongest evidence are largely free through the NHS, while the tests with the weakest evidence are the ones being sold to you.

The evidence-based pathway, step by step

Step 1 — Keep a structured food and symptom diary for two to three weeks

Record what you ate, the time, the symptom, its severity out of ten, and the delay between eating and onset. Also log sleep, stress, alcohol, caffeine, menstrual cycle phase and medications — all of which independently affect gut symptoms. This costs nothing and is more informative than most paid tests. Note that certain foods commonly cause bloating in almost everyone, which is not the same as intolerance.

Step 2 — See your GP and rule out disease first

Ask specifically about coeliac serology, full blood count, ferritin, CRP, thyroid function and faecal calprotectin. Do not remove gluten before coeliac testing. Also review your medications — proton pump inhibitors, metformin, iron and NSAIDs all cause gut symptoms that can masquerade as food intolerance. See long-term effects of omeprazole, metformin and stomach side effects and iron supplements and constipation.

Step 3 — Use targeted validated testing where indicated

Breath testing if lactose or fructose malabsorption or SIBO is suspected. Specific IgE if reactions are rapid. Further imaging or endoscopy if red flags are present. Consider bile acid malabsorption if you have chronic watery diarrhoea, especially after gallbladder surgery — it is frequently mistaken for food intolerance.

Step 4 — Run a proper elimination and reintroduction

One food group at a time. Two to four weeks of complete removal. Then a deliberate, graded reintroduction. Repeat the challenge at least once to confirm. Involve a registered dietitian where possible — check registration on the HCPC register.

Step 5 — Personalise and reintroduce as much as you safely can

The goal is the widest tolerable diet, not the narrowest. Most intolerances are dose-dependent, so the useful question is "how much can I have?" rather than "can I have this?". Rebuild fibre and diversity gradually — see how to increase fibre and the best foods for gut health.

Common intolerances and how they are actually diagnosed

Lactose intolerance

The most common true intolerance. Diagnosed by hydrogen breath test, a structured dairy challenge, or a therapeutic trial of lactose reduction with reintroduction. Most people retain some lactase and tolerate hard cheese, yoghurt and small amounts of milk.

FODMAP sensitivity

Not a disease but a threshold effect: poorly absorbed short-chain carbohydrates draw water into the bowel and ferment rapidly. Identified through the low FODMAP protocol with reintroduction, not through a blood test. Relevant to a large proportion of people with IBS — see supplements for IBS and supplements for bloating.

Histamine intolerance

Proposed to result from reduced diamine oxidase activity relative to dietary histamine load. Diagnosis remains clinical — a supervised low-histamine trial followed by reintroduction. Blood DAO levels are not a reliable standalone diagnostic. See histamine intolerance in the UK.

Non-coeliac gluten or wheat sensitivity

Diagnosed only after coeliac disease and wheat allergy have been excluded, and only where symptoms consistently return on blinded rechallenge. Fructans in wheat may explain a proportion of cases, which is why some people who improve on a gluten-free diet are actually responding to a FODMAP reduction.

Wheat is one of the most commonly flagged foods on IgG panels — largely because it is one of the most commonly eaten. Image: Wikimedia Commons, freely licensed.

Caffeine, alcohol, sulphites and salicylates

These are pharmacological rather than immune reactions. There is no validated blood test; identification is by structured trial and dose-finding.

Where supplements and gut support fit in

Supplements do not diagnose anything, and no supplement can substitute for coeliac testing or investigation of red flag symptoms. Their role is supportive, alongside a properly identified dietary trigger.

Where the evidence is reasonable, they can help. Lactase enzymes taken with dairy can reduce symptoms in lactose intolerance. Enteric-coated peppermint oil has trial support for IBS symptoms — see peppermint oil capsules for IBS. Specific probiotic strains have strain-specific evidence for particular symptoms; our guides to the best probiotics in the UK, how to choose a probiotic and whether probiotics actually work cover this honestly, including where the evidence is thin.

If you are rebuilding a restricted diet, focus on the gut lining and fibre intake rather than more exclusions. Readers often look at gut barrier function, prebiotic supplements and butyrate supplements. Reintroduce fermentable fibre gradually — going too fast after a period of restriction reliably causes bloating and is often misread as a new intolerance. Browse the full Welzo gut health collection.

Red flags: when to see a GP urgently

Do not attempt to manage these with an elimination diet. Book an urgent GP appointment if you have:

• Unintentional weight loss
• Blood in your stool, or black tarry stools
• A persistent change in bowel habit lasting more than three weeks, particularly if you are over 50
• Difficulty or pain on swallowing
• Persistent vomiting
• Iron deficiency anaemia
• A palpable abdominal or rectal mass
• Night-time symptoms that wake you from sleep
• A family history of bowel cancer, coeliac disease or IBD alongside new symptoms

Call 999 if you have swelling of the lips, mouth, throat or tongue, difficulty breathing, or sudden collapse after eating. That is anaphylaxis, not intolerance.

How to read a private test provider's claims

The Advertising Standards Authority and the Committee of Advertising Practice have published specific guidance on marketing for food allergy and intolerance testing, and have upheld complaints against providers making unsupported diagnostic claims. Useful questions before you buy:

• What biological marker is measured, and what does a positive value mean? If the answer is vague, that is the answer.
• Is there published, peer-reviewed evidence that this specific test predicts symptoms? Not that the lab is accredited — that the test predicts symptoms.
• Does it distinguish intolerance from allergy and coeliac disease? If not, it cannot safely be your first step.
• Is a qualified clinician or registered dietitian involved in interpreting results?
• Does the provider tell you to see your GP first? Responsible ones do.

Frequently asked questions

Are food intolerance tests available on the NHS?

Not in the form sold commercially. The NHS tests for conditions with validated diagnostics — coeliac disease, IgE-mediated food allergy, lactose malabsorption via breath testing, and inflammatory bowel disease. For suspected food intolerance, the NHS route is a GP assessment to exclude other conditions, followed by referral to a dietitian for a supervised elimination and reintroduction diet.

Are IgG food intolerance tests accurate?

They accurately measure IgG antibodies, but those antibodies do not indicate intolerance. The EAACI Task Force concluded that food-specific IgG4 reflects repeated exposure and immunological tolerance rather than hypersensitivity. The NHS, NICE, the BDA and the AAAAI all advise against using IgG results to guide dietary exclusion.

What is the most accurate food intolerance test in the UK?

There is no single test. The most accurate approach is a supervised elimination and reintroduction diet, supported where clinically indicated by hydrogen and methane breath testing, coeliac serology and faecal calprotectin. That combination outperforms any commercial panel.

Can a hair test detect food intolerance?

No. Hair contains no food-specific antibodies or immune cells and no record of digestive function. NICE lists hair analysis among tests that should not be used in diagnosing food allergy, and there is no evidence base supporting its use for intolerance.

How long does it take for food intolerance symptoms to appear?

Usually a few hours after eating, though it can range from around 30 minutes to 48 hours depending on mechanism. Lactose and FODMAP symptoms often appear within two to six hours. This delay is exactly why a written food and symptom diary is more useful than memory.

Should I stop eating gluten before a coeliac test?

No — this is the single most important thing to get right. You must be eating gluten regularly, generally at least one gluten-containing meal daily for six weeks before both the blood test and any biopsy. Removing gluten beforehand is the most common cause of a false negative and may mean you never get a diagnosis.

Is bloating always a sign of food intolerance?

No. Bloating is also caused by IBS, constipation, SIBO, coeliac disease, gastroparesis, hormonal fluctuations, swallowed air and medication side effects. Certain foods cause gas in almost everyone, which is normal fermentation rather than intolerance. Persistent new bloating in women, especially over 50, should always be assessed by a GP.

Can food intolerances develop later in life or go away?

Yes, in both directions. Lactase activity commonly declines with age. Intolerance can also appear temporarily after gastroenteritis, a course of antibiotics or a period of gut inflammation, and may resolve as the gut recovers. This is one reason periodic, careful reintroduction matters rather than permanent exclusion. See probiotics after antibiotics.

Do gut microbiome tests identify food intolerances?

Not reliably. Microbiome sequencing describes bacterial composition, which is genuine science, but the models translating that into personalised "avoid" food lists are not validated to diagnostic standards. Treat any food list generated from a microbiome report as a hypothesis to test, not a diagnosis.

What should I do if I have already taken an unreliable test?

Do not eliminate the whole list. Take your one or two most suspected foods, discuss them with your GP or a registered dietitian, and run a proper elimination and reintroduction on those alone. Make sure coeliac disease has been excluded while you are still eating gluten, and reintroduce anything you have already removed without clear evidence it was causing symptoms.

The bottom line

If you are searching for a food intolerance test in the UK, the honest answer is that the tests being advertised to you most aggressively are the ones with the weakest evidence, and the approaches with the strongest evidence are largely available free through your GP. Your symptoms are real. The shortcut being sold is not.

Start with a food and symptom diary, get disease excluded properly, use validated testing where it is indicated, then run a structured elimination and reintroduction with dietitian support. It is slower than posting a hair sample. It is also the only route that reliably tells you the truth.

References

1. NHS. Food intolerance. NHS.uk.
2. NHS. Food allergy. NHS.uk.
3. British Dietetic Association. Food Allergy and Food Intolerance Testing — Food Fact Sheet.
4. British Dietetic Association. Food Allergy and Food Intolerance — Food Fact Sheet.
5. NICE. Food allergy in under 19s: assessment and diagnosis (CG116).
6. Stapel SO, Asero R, Ballmer-Weber BK, et al. Testing for IgG4 against foods is not recommended as a diagnostic tool: EAACI Task Force Report. Allergy. 2008;63(7):793–796.
7. Bock SA. AAAAI support of the EAACI Position Paper on IgG4. J Allergy Clin Immunol. 2010;125(6):1410.
8. Carr S, Chan E, Lavine E, Moote W. CSACI Position statement on the testing of food-specific IgG. Allergy Asthma Clin Immunol. 2012;8:12.
9. Lewith GT, Kenyon JN, Broomfield J, et al. Is electrodermal testing as effective as skin prick tests for diagnosing allergies? A double blind, randomised block design study. BMJ. 2001;322(7279):131–134.
10. Semizzi M, Senna G, Crivellaro M, et al. A double-blind, placebo-controlled study on the diagnostic accuracy of an electrodermal test in allergic subjects. Clin Exp Allergy. 2002;32(6):928–932.
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13. Mitchell N, Hewitt CE, Jayakody S, et al. Randomised controlled trial of food elimination diet based on IgG antibodies for the prevention of migraine like headaches. Nutr J. 2011;10:85.
14. Singh P, Chey WD, Takakura W, et al. A Novel, IBS-Specific IgG ELISA-Based Elimination Diet in Irritable Bowel Syndrome: A Randomized, Sham-Controlled Trial. Gastroenterology. 2025.
15. De Geyter C, Van de Maele K, Hauser B, Vandenplas Y. Hydrogen and Methane Breath Test in the Diagnosis of Lactose Intolerance. Nutrients. 2021;13(9):3261.
16. Coeliac UK. Coeliac Disease Diagnosis: Tests and Steps.
17. Coeliac UK. Home tests for coeliac disease.
18. Guts UK. Coeliac Disease.
19. Advertising Standards Authority / CAP. Health: Food Allergy/Intolerance testing.
20. NICE. Irritable bowel syndrome in adults: diagnosis and management (CG61).

About the author

Dr Zeeshan Afzal, MBBS is a practising medical doctor and Medical Content Lead at Welzo. He writes and clinically reviews Welzo's digestive health content, with a focus on translating UK clinical guidance and peer-reviewed evidence into practical guidance for patients. All Welzo health content is reviewed against current NHS, NICE and specialist society guidance.

Medical disclaimer

This article is for general information and is not a substitute for personalised medical advice, diagnosis or treatment. Do not delay seeking advice from your GP because of something you have read here. Do not remove gluten from your diet before coeliac testing. If you have red flag symptoms, contact your GP promptly. If you have symptoms of anaphylaxis, call 999 immediately. Supplements are not intended to diagnose, treat, cure or prevent any disease.