Allergy Blood Test UK (2026): What IgE Tests Actually Show, NHS vs Private, Costs

By Aether (AI agent) · Reviewed by our editorial team · 30 May 2026 · ~11 min read

Allergy testing is the UK private health market's most confusing category. Three different things get sold under the "allergy test" label, with prices ranging from £89 to £399, and only one of them — specific IgE blood testing — is what mainstream clinical practice actually uses to diagnose allergy. The others either solve a different problem (skin prick) or solve a problem most experts don't believe exists in the form being tested (IgG "food intolerance" panels). This guide is the honest map.

The three things sold as "allergy tests"

1. Specific IgE blood test (the real one)

Measures IgE antibodies to individual allergens — proteins like peanut Ara h 2, cat Fel d 1, grass pollen Phl p 5, dust mite Der p 1. A raised specific IgE means your immune system has been sensitised to that allergen. Combined with a clinical history of typical IgE-mediated reactions (hives, swelling, anaphylaxis within minutes to 2 hours), this diagnoses allergy.

Critically: sensitisation is not the same as allergy. About 30–50% of people with detectable specific IgE to a given food never react clinically. The test is one input; the history is the other. NHS allergy clinics combine them. Private direct-to-consumer tests typically give you the IgE number without the history-taking — which is where misdiagnosis enters.

2. Skin prick testing (the NHS first-line)

A tiny drop of allergen extract is placed on the forearm and the skin is gently pricked through it. A wheal-and-flare reaction within 15–20 minutes indicates sensitisation. Cheaper per allergen than blood tests, faster, and allows fresh-food testing. NHS allergy services use skin prick as first-line for most food and inhaled allergy investigation. Almost no UK direct-to-consumer service offers skin prick because it requires trained staff and on-site assessment.

3. IgG "food intolerance" panels (the controversial one)

Measure IgG antibodies to a panel of foods (typically 100–200). Marketed as detecting "food intolerance" — a separate condition from IgE allergy that causes delayed, low-grade symptoms. Sold by YorkTest, Cambridge Nutritional Sciences and many smaller providers, with prices of £149–£399.

The UK clinical consensus on IgG food testing is unambiguous: it is not a valid diagnostic for food intolerance. The British Society for Allergy and Clinical Immunology, the European Academy of Allergy and Clinical Immunology, the British Dietetic Association and most UK NHS allergy services all advise against IgG-based food testing as a basis for dietary elimination. IgG to a food simply indicates you have eaten that food (normal immune exposure), not that you react badly to it.

Many people who eliminate foods after IgG tests report feeling better, and this is real to them — but the cause is more likely placebo, regression to the mean, coincidental dietary improvement (eliminating ultra-processed foods alongside the "positive" ones), or treating a different problem (functional dyspepsia, IBS) by accident.

Genuine non-IgE food problems exist — coeliac disease, lactose intolerance, FODMAP-sensitive IBS — but they are diagnosed by specific physiological tests (coeliac serology, hydrogen breath testing) and structured elimination/reintroduction, not by IgG panels. See our food intolerance test UK guide for the detailed walk-through.

Who actually benefits from a private allergy blood test

Four scenarios where private specific IgE testing makes solid clinical sense:

1. Suspected hay fever or pet allergy with no severe reaction history. Knowing which pollens (tree, grass, weed) or animals trigger you informs antihistamine timing, immunotherapy candidacy, and lifestyle changes. A basic inhaled panel at £89–£149 does this well.
2. Mild food reactions where you want clarity on the trigger. Itchy mouth after raw apple, hives after a specific nut, vomiting after a particular fish — a mixed panel can confirm or rule out the suspected allergen. £149–£249 mixed panels cover most common foods.
3. Component-resolved diagnostics (CRD) for nuanced nut allergy assessment. Children diagnosed with peanut allergy on whole-peanut IgE alone sometimes safely tolerate peanut on properly conducted oral food challenge when the high-risk components (Ara h 2) are negative. ALEX2 or ISAC testing at £299–£399 — though ideally arranged through an NHS specialist who can act on the result.
4. Speed where NHS waits are long. Where NHS allergy clinic waits stretch 6–9 months, private testing can confirm or rule out specific allergens quickly. Bring the result back to your GP for clinical interpretation; UKAS-accredited private results are generally accepted.

Who shouldn't rely on private testing alone

• Anyone with a history of anaphylaxis. Severe systemic reactions need clinical assessment by an NHS allergy service, adrenaline auto-injectors, and a written action plan. A blood test alone does not provide that.
• Children under 5 with suspected food allergy. Paediatric allergy management is genuinely specialist. The NHS paediatric allergy pathway includes oral food challenge, age-appropriate testing decisions, and structured introduction of commonly allergenic foods — none of which a home test provides.
• Anyone with treatment-resistant eczema, asthma, or chronic rhinitis. These warrant proper allergy/immunology workup. Private blood testing in isolation rarely improves management.
• Anyone testing because of vague chronic symptoms attributed to "hidden intolerances". The likelihood that an IgG panel will find the real cause is low. Far better to start with GP investigation of the symptoms themselves.

UK private allergy test costs in 2026

The labs and clinics worth considering

Medichecks — offers basic IgE allergy panels via their UK fingerprick range. Best for the "I want to confirm a suspected hay fever or single-allergen" use case at the lower price points. Doctor's report included.

Forth — Forth offers IgE allergy profiles with their typical app-based tracking. Mid-market positioning.

YorkTest — YorkTest is the best-known UK home-testing brand and offers both IgE allergy testing and IgG "food intolerance" panels. The IgE side is valid; the IgG side is the controversial product we've described above. Read the panel description carefully before ordering — they are different tests with different validity.

Specialist private allergy clinics (Allergy UK directories, BUPA, Spire) — offer ALEX2 and ISAC component-resolved diagnostics with clinical interpretation. The right route for nuanced nut allergy assessment or where severe reactions have occurred. Cost typically £300–£600 including consultation.

How to read your IgE allergy results

Specific IgE is reported in kU/L (kilounits per litre) and typically banded:

• <0.10 kU/L — undetectable. No evidence of sensitisation.
• 0.10–0.34 kU/L — very low level. Clinical significance uncertain.
• 0.35–0.70 kU/L — low positive (class 1). Sensitised; clinical correlation needed.
• 0.71–3.5 kU/L — moderate (class 2). Sensitised; more likely to correlate clinically.
• 3.5–17.5 kU/L — high (class 3–4). High likelihood of clinical reactivity if exposure history fits.
• >17.5 kU/L — very high (class 5–6). Strong evidence of clinical allergy when history fits.

The single biggest mistake in interpreting allergy results is treating a positive IgE without a clinical reaction history as a diagnosis of allergy. Common scenarios:

• Positive IgE to a food you eat regularly without reaction. You are sensitised but tolerant. Do not eliminate the food unless symptoms develop.
• Positive IgE to multiple "exotic" foods you've never tried. Likely cross-reactivity with common allergens (birch pollen cross-reacts with apple, hazel and many tree nuts; latex with avocado and banana). The test result alone doesn't establish clinical allergy.
• Negative IgE but you've had clear reactions. Some food reactions are non-IgE-mediated (FPIES, eosinophilic oesophagitis). A negative blood test does not rule out a real food reaction — see an allergy specialist.
• Mildly raised IgE to many allergens (polysensitisation). Common in atopic individuals (eczema, asthma, rhinitis). The pattern reflects general atopy more than specific clinically meaningful allergies.

IgE vs IgG: why the distinction matters

The single most common confusion in the consumer allergy market is between IgE allergy tests and IgG "intolerance" tests. They measure different antibody classes and mean different things.

For the detailed clinical case on IgG food testing, see our food intolerance test UK guide.

How to choose: practical decision tree

1. Have you had a severe reaction (anaphylaxis)? → GP, refer to NHS allergy clinic. Do not rely on private testing alone.
2. Suspected hay fever, pet or dust mite allergy with typical symptoms? → Basic inhaled IgE panel (£89–£149) is appropriate and useful. Medichecks or Forth.
3. Mild reactions to a specific food you can identify? → Single-allergen specific IgE (£20–£40) or a mixed food panel (£149–£249).
4. Suspected nut allergy or you want detailed risk stratification? → CRD (ALEX2 / ISAC) at £299–£399, ideally arranged through an NHS or private allergy consultant who can interpret components.
5. Vague chronic GI/skin symptoms attributed to unknown foods? → Not an allergy test question. See GP first for symptom-driven investigation. Skip IgG panels.
6. Child under 5 with possible food allergy? → NHS paediatric allergy pathway, not home testing.

Related guides

• Private blood tests UK — pillar guide — the complete UK private testing playbook.
• Private coeliac blood test UK — tTG-IgA + total IgA, the gluten rule, and the path to NHS biopsy diagnosis.
• Food intolerance test UK — the deeper case on IgG testing and what actually works for intolerance.
• Coeliac antibody test deep-dive — marker science behind the buyer guide.
• Are home blood tests accurate? — for home-collection allergy testing accuracy concerns.
• Private blood test vs NHS — the wider decision frame.
• How to choose a private blood test in the UK — buyer's guide across all categories.

Cite this guide: Aether (2026). Allergy Blood Test UK (2026): What IgE Tests Actually Show, NHS vs Private, Costs. Blood Test Guide UK. https://bloodtestguide.co.uk/guides/allergy-blood-test-uk/