If you're reacting badly to certain foods, the first thing to work out isn't which food — it's whether you're dealing with a true food allergy or a food intolerance. They're genuinely different conditions, diagnosed in different ways, and confusing the two can mean choosing the wrong test entirely. Here's how each is properly identified, and why our Allergy & Intolerance Combined Test covers both angles in one kit.
Table of Contents
The Key Difference: Immune System vs. Digestion
A food allergy involves your immune system producing IgE antibodies in response to a specific food protein, which can trigger a rapid, sometimes severe reaction — anything from hives to, in serious cases, anaphylaxis.
A food intolerance doesn't involve the immune system at all. It's typically a digestive issue — your body struggling to process a particular food or food component — and reactions tend to be delayed, milder, and centred around symptoms like bloating, gas, or stomach discomfort.
Because the mechanisms are different, so is the correct way to test for each.
Food Allergy Tests
For a genuine, immune-mediated allergy, two methods are clinically established:
- Skin prick test: a small amount of allergen extract is placed on the skin, which is then lightly pricked. A raised, itchy bump indicates a reaction. Usually done in a clinical setting.
- Specific IgE blood test: a blood sample is checked for allergy-specific antibodies linked to particular foods. This is the method used in our IgE-based tests, including the Premium Allergy Test and Food Allergy Test.
For anyone with a history of severe reactions, an oral food challenge — supervised by a medical professional in a clinical setting, given the risk involved — remains the gold standard, but IgE blood testing is a genuinely validated, medically recognised starting point.
Food Intolerance Tests
Food intolerance is more difficult to test for conclusively, and it's worth being upfront about this rather than overselling it. The NHS and British Dietetic Association (BDA) note that there's no single, universally validated laboratory test for general food intolerance — the most reliable approach remains a supervised elimination diet, where suspected trigger foods are removed for several weeks and then carefully reintroduced to monitor symptoms.
Commercial IgG antibody testing — the method used in part of our Combined Test — is a different approach. It's worth understanding what it actually measures: IgG antibodies largely reflect foods your body has been repeatedly exposed to, rather than definitively confirming an intolerance. We offer it because many customers find it a useful starting point for identifying patterns worth investigating further, not because it replaces a proper elimination diet or medical guidance — and we'd rather be clear about that than let you assume otherwise.
For specific, well-defined conditions like lactose intolerance, clinically validated tests do exist (such as a hydrogen breath test), and these are worth discussing with your GP if that's specifically what you suspect.
Why We Offer a Combined Test
Because allergy and intolerance symptoms can overlap — and because most people aren't sure which one they're actually dealing with — our Allergy & Intolerance Combined Test checks both IgE and IgG markers in one kit. This gives you a genuinely broader starting picture than choosing one methodology blind, though it doesn't replace the need to discuss results with your GP, particularly if allergy symptoms are involved.
Which Should You Choose?
- Had a fast, severe, or breathing-related reaction? Speak to your GP first — this needs proper clinical evaluation, not a home test alone. Once you're ready to explore testing, our Food Allergy Test uses the clinically established IgE method.
- Reacting to something in your environment, not food? Our Indoor & Outdoor Allergy Test or Food & Environmental Allergy Test may be a better fit.
- Reacting on skin contact specifically? The Skin Allergy Test is built for this.
- Mild, delayed, digestive-type symptoms, and not sure if it's allergy or intolerance? The Allergy & Intolerance Combined Test covers both angles in one kit.
Whatever you choose, we'd recommend treating any test result — ours included — as a starting point for a conversation with your GP or a registered dietitian, not a final diagnosis on its own.
Comparing Our IgE Allergy Tests
All five of our IgE tests use the same clinically established methodology — the question is which specific triggers you want checked. Here's how they compare:
| Test | Best for | Covers |
|---|---|---|
| Premium Allergy Test | Broadest single-test coverage | The widest combined panel of food and environmental allergens |
| Food Allergy Test | Suspected reactions to specific foods | Common food allergens only |
| Food & Environmental Allergy Test | Symptoms that could be food- or environment-related | A combined food and environmental panel |
| Indoor & Outdoor Allergy Test | Suspected pollen, dust mite, mould, or pet dander triggers | Environmental allergens only, indoor and outdoor |
| Skin Allergy Test | Reactions from skin contact specifically | Common contact and skin-reaction allergens |
Not sure which panel is right for you? As a general rule: if your symptoms could come from several different directions (food, pollen, pets), the Premium or Food & Environmental test gives you the broadest first look. If you already have a strong suspicion — say, symptoms that only happen around pets, or only after eating — a more targeted test may be the better starting point.
For anyone with a history of severe reactions, an oral food challenge — supervised by a medical professional in a clinical setting, given the risk involved — remains the gold standard, but IgE blood testing is a genuinely validated, medically recognised starting point. See our full guide to choosing the best allergy test for more detail on IgE testing specifically.
FAQs
Can I have both a food allergy and a food intolerance at the same time?
Yes — the two conditions aren't mutually exclusive, and it's entirely possible to have a genuine allergy to one food and a digestive intolerance to another, which is part of why combined testing can be useful as a broader starting picture.
Is IgG testing scientifically proven to diagnose food intolerance?
No — and we want to be upfront about that. Major health bodies including the BDA note that IgG antibodies reflect food exposure rather than confirming intolerance. We include IgG testing as part of our Combined Test because many customers find it a useful starting point, not as a substitute for a supervised elimination diet or medical advice.
Should I stop eating a food just because a test flags it?
Not without further investigation. Any test result — from any provider — is a starting point for tracking symptoms or discussing with a healthcare professional, not an instruction to eliminate a food outright, particularly since unsupervised restrictive diets can create their own nutritional risks.
How long does the Combined Test take?
Get your results within 3 working days.
Understanding whether you're dealing with a food allergy or a food intolerance — or possibly both — is the first real step toward managing your symptoms properly. Whichever path fits your situation, treating your results as a starting point for further conversation with a healthcare professional will always serve you better than treating them as a final answer.
