Something is making you feel unwell and you don't know what it is. Maybe it's the headaches that come on after certain meals. The bloating that appears unpredictably. The skin that flares up without obvious cause. The fatigue that descends after eating and won't lift. The runny nose that never quite goes away. The eyes that itch through spring and summer. The gut that never feels quite settled.
You've tried cutting things out. You've kept food diaries. You've googled your symptoms more times than you can count. And you still don't have a clear answer.
A private allergy and intolerance blood test is often the fastest, clearest route to finally understanding what your body is reacting to — and why.
The difference between an allergy and an intolerance
These two terms are used interchangeably in everyday language, but they describe genuinely different physiological processes — and the distinction matters for how each is identified and managed.
A true allergy is an immune system response. When you encounter a substance you're allergic to — a food, pollen, pet dander, dust mites, latex, or any number of other triggers — your immune system produces IgE antibodies as a defence. These antibodies trigger the release of histamine and other chemicals that cause the classic allergic response: hives, swelling, itching, sneezing, runny nose, watery eyes, difficulty breathing, and in severe cases anaphylaxis. True allergic reactions are typically rapid — symptoms appear within minutes to a couple of hours of exposure.
A food intolerance involves a different mechanism — typically IgG antibodies rather than IgE. IgG reactions are slower and more complex. Symptoms can appear hours or even days after exposure to the trigger food, making them genuinely difficult to identify without testing. Common food intolerance symptoms include bloating, abdominal pain, diarrhoea, constipation, headaches, brain fog, fatigue, skin conditions like eczema and acne, and joint pain. Because the reaction is delayed and the symptoms are so varied, many people live with food intolerances for years without identifying the cause.
Understanding which mechanism is driving your symptoms is the essential first step — and blood testing is the most reliable way to determine this.
What blood testing reveals
At Boost & Glow, Lucy carries out venous blood draws — the same method used in hospitals and GP surgeries — to test for both IgE-mediated true allergies and IgG-mediated food intolerances across a comprehensive range of panels.
IgE allergy testing
IgE testing measures the level of specific IgE antibodies in your blood — the antibodies your immune system produces when it encounters something it has identified as a threat. Elevated IgE antibodies to a specific substance confirm a true allergic response to that substance.
Our IgE panels cover a wide range of environmental allergens including grass pollen, tree pollen, weed pollen, house dust mites, cat and dog dander, mould spores, and latex. They also cover food allergens including the fourteen major food allergens recognised by UK law — peanuts, tree nuts, milk, eggs, wheat, soya, fish, shellfish, sesame, celery, mustard, lupin, molluscs, and sulphites — alongside many additional food groups.
Knowing your specific IgE profile gives you precise information about which substances trigger your immune response, allowing you to manage exposure and make informed decisions about treatment options including antihistamines, allergen immunotherapy, and emergency medication.
IgG food intolerance testing
IgG testing measures your body's IgG antibody response to a wide range of foods. Elevated IgG antibodies to specific foods indicate that your immune system is reacting to those foods — producing a slower, lower-grade inflammatory response that accumulates over time and drives the chronic symptoms that many people struggle to pinpoint.
Our IgG panels test reactions to an extensive range of foods spanning every food category — dairy, gluten and grains, meats, fish and seafood, fruits, vegetables, nuts, seeds, legumes, spices, and more. The breadth of testing is important because IgG reactions are rarely to a single food — most people with significant food intolerance react to multiple foods across different categories.
Understanding your IgG profile allows you to implement a targeted elimination protocol — removing the specific foods your body is reacting to rather than following a generic elimination diet that may or may not address your actual triggers.
The first-line allergy panel
For those who want to start with a focused screening rather than a comprehensive panel, our Allergy First-Line Panel covers the most common environmental and food allergens in a single test — giving you a clear picture of the most likely suspects before deciding whether a broader panel is needed. At £160, it's the most accessible entry point into allergy and intolerance testing and identifies the majority of common reactions in one draw.
Symptoms that suggest allergy or intolerance testing is worth doing
The range of symptoms driven by allergies and food intolerances is broader than most people realise. If you experience any of the following regularly, testing is worth considering.
Digestive symptoms including bloating, abdominal discomfort, nausea, diarrhoea, constipation, or irritable bowel symptoms that don't have a clear cause. Skin symptoms including eczema, urticaria (hives), acne, rosacea, or persistent unexplained rashes. Respiratory symptoms including chronic rhinitis (runny or blocked nose), frequent sneezing, persistent cough, or worsening asthma. Neurological symptoms including brain fog, headaches, migraines, or difficulty concentrating — all of which have been linked to chronic food intolerance in research. Fatigue that appears after eating or has no clear cause. Joint pain or inflammation that fluctuates without explanation. Recurring ear infections or glue ear, particularly in children.
In many of these cases, the person has been seen by their GP, told their bloods are normal, and given no clear direction. Private allergy and intolerance testing provides the specific information that standard healthcare doesn't routinely offer.
What happens after your results
Understanding what you're reacting to is the beginning, not the end. At Boost & Glow, Lucy will walk you through your results in detail — explaining what each finding means, which reactions are most significant, and what a realistic management plan looks like.
For IgE allergies, this might involve guidance on avoidance strategies, discussion of antihistamine options, advice on when to carry emergency medication, and referral to an NHS allergist where appropriate. For IgG food intolerances, Lucy will guide you through a structured elimination and reintroduction protocol — removing reactive foods for a defined period to allow inflammation to settle, then systematically reintroducing them to establish tolerance thresholds.
Sam is also available to build a nutrition plan around your intolerance results — ensuring that any dietary restrictions are managed in a way that maintains nutritional completeness and doesn't create secondary deficiencies.
Why private testing rather than NHS
NHS allergy testing is available but limited in scope and often difficult to access. Referrals to allergy clinics can involve significant waiting times, and the panels available on the NHS are typically restricted to the most common allergens. IgG food intolerance testing is not routinely available through the NHS at all.
Private testing with Boost & Glow offers same-week appointments, comprehensive panels covering a far broader range of allergens and intolerances than NHS testing, results returned promptly with personalised interpretation from Lucy, and the option to combine allergy testing with a broader health screen in the same appointment.
At Boost & Glow
Lucy carries out all allergy and intolerance blood testing using venous draws at our clinic in Epping or at your home across Essex, Hertfordshire, and London. We offer a full range of panels — from the focused first-line screen to comprehensive IgE and IgG panels covering hundreds of substances — so the right level of testing can be matched to your specific symptoms and concerns.
If you've been living with symptoms you can't explain and haven't been able to get answers, a private allergy blood test is a direct route to clarity.
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