Allergy and immunology testing (Allergy and clinical immunology investigations)
Tests used by allergy and immunology specialists to help work out whether symptoms are caused by an allergy or an immune problem, and to guide a safe management plan.
✓ Medically reviewed by a GMC-registered consultant · last reviewed September 2026 · next review September 2027 · how we review
In short
- These tests help investigate allergy or immune problems, but only make sense alongside your symptoms and history.
- A positive allergy test shows sensitisation, which is not the same as being allergic — many people test positive without reacting.
- Choosing the right test for the right question matters; broad 'allergy screens' and unvalidated commercial tests cause more harm than help.
- Results should lead to a clear plan — what to avoid, what is safe, and when to seek help — not just a list of positives.
A plain-English summary. The detail — including risks and recovery — is below.
At a glance
A general guide. Your specialist will give you advice for your situation.
Can support or rule out a suspected allergy or immune problem
Untargeted 'total allergy screens' ordered without a clear clinical question — they generate misleading positives.
Skin prick results are read after about 15–20 minutes; small bumps settle within an hour or so.
A clear, written explanation of results and what they mean for daily life.
Skin prick results are read after about 15–20 minutes; small bumps settle within an hour or so.
Patches are removed and the skin is read over two or more days to detect delayed reactions.
Blood test results (specific IgE or immune tests) return and are interpreted alongside your history.
A supervised challenge test is done on another day in hospital and may take several hours including observation.
What is allergy and immunology testing?
Allergy and immunology testing covers a range of tests used to investigate possible allergies (such as to foods, drugs, pollens, animals, house dust mite, latex or insect stings) and possible problems with the immune system (such as recurrent or unusual infections, or suspected immune deficiency).
The tests are tools, not answers in themselves. A specialist chooses them based on your symptoms and history, then interprets the results in that context. A test result on its own — especially a positive allergy test — does not prove that something is causing your symptoms.
Common allergy tests include skin prick tests, blood tests for specific IgE (allergy antibodies), patch tests for delayed skin reactions, and, in selected cases, supervised challenge tests in hospital. Immune tests may include blood counts, antibody (immunoglobulin) levels, vaccine-response checks and more specialised tests, depending on the question.
The goal is a clearer diagnosis and a sensible plan: what to avoid, what is safe, whether treatment is needed, and what to do in an emergency. Importantly, testing can also rule things out and stop unnecessary, restrictive avoidance.
Types, options & approaches
There may be different ways to do this. The right approach depends on the clinical question and your circumstances.
Skin prick vs blood IgE vs patch testing
| Feature | Skin prick | Blood IgE | Patch test |
|---|---|---|---|
| Reaction type | Immediate (IgE) | Immediate (IgE) | Delayed (contact) |
| Result speed | 15–20 minutes | Days | 48–96 hours |
| Antihistamines | Must stop first | Not affected | Not affected |
| Main use | Foods, pollens, pets, stings | When skin testing isn't possible | Skin contact allergens |
Each test answers a different question. A positive result means sensitisation or a skin reaction, which only matters when it fits your symptoms. None of these are validated as general 'health screens'.
Preparing for your test
- Write down your symptoms, when they happen, how quickly they come on, and what seems to trigger them.
- Bring a full list of medicines and supplements, and ask whether to stop antihistamines before skin prick testing and for how long.
- Bring any previous test results, hospital letters or records of reactions.
- Keep packaging or photos of foods, products or medicines you think may be involved.
- For suspected immune problems, note your history of infections, hospital admissions and vaccinations.
- For patch testing, avoid sunbeds and strong sun on your back beforehand and plan for several clinic visits over a few days.
- Do not deliberately re-expose yourself to a suspected trigger at home to 'test' it.
What happens
Most appointments begin with a detailed conversation about your symptoms and history, which decides what testing is appropriate.
For skin prick testing, drops are placed on your forearm and the skin is pricked through each one; bumps are measured after about 15–20 minutes. Blood may be taken for specific IgE or immune tests and sent to a laboratory. Patch testing involves applying patches to your back that stay in place for about 48 hours, with the skin read on later visits.
Where needed, a supervised challenge test is arranged on a separate day in hospital, with staff and facilities ready to treat any reaction.
The specialist should explain what each test is for, what the results mean for you, and what to do next — including any emergency plan if a serious allergy is confirmed or suspected.
Is this test right for me?
A good consultation should explore whether it's the right choice for you now — including reasons to wait or consider something else.
May not be suitable if…
- Untargeted 'total allergy screens' ordered without a clear clinical question — they generate misleading positives.
- Commercial or alternative tests (IgG food intolerance panels, hair analysis, bioresonance, kinesiology), which are not validated for diagnosing allergy.
- Skin prick testing while taking antihistamines, which can mask reactions.
- Allergy testing when symptoms clearly point to a non-allergic cause that needs a different specialty.
Delay or rearrange if…
- You are currently taking antihistamines and cannot stop them before skin prick testing.
- You are acutely unwell or have a flare of eczema over the test sites.
- Key previous results or hospital letters are missing but obtainable.
- A challenge test is being considered but full resuscitation facilities are not available.
Alternatives to discuss
- A careful clinical history and symptom diary, which sometimes give the answer without testing.
- A supervised elimination and reintroduction plan for suspected food triggers, under specialist guidance.
- Referral to a different specialty if symptoms are not allergic in nature.
- Watchful waiting where symptoms are mild and intermittent.
Before you decide
Use this as a shared-decision checklist. The aim is not just “can this be done?”, but whether it is right for you, now, with the risks and alternatives clearly understood.
What matters most to me?
Think about symptoms, daily life, work, caring responsibilities, sport, fertility, travel, appearance and anxiety — the right choice depends on your priorities, not just the medical facts.
What are all my options?
Ask about waiting, monitoring, medicines, rehabilitation, a smaller or larger procedure, a different test, NHS referral, or a second opinion where that would help.
What would make me pause?
Active infection, pregnancy, unstable medical problems, smoking, medicines that increase bleeding, poor support at home, or feeling pressured are all reasons to slow down and get tailored advice.
What happens if I do nothing today?
For some problems, waiting is safe; for others, delay can make treatment harder. A good consultation should explain the trade-off in plain English.
Benefits
- Can support or rule out a suspected allergy or immune problem
- Helps avoid unnecessary, restrictive avoidance when a trigger is excluded
- Guides safe choices about foods, medicines or environments
- Can identify an immune deficiency that needs treatment or monitoring
- Provides a clearer plan and, where needed, an emergency plan
- Can reassure when symptoms are not due to allergy
Risks & complications
- Mild itching or small bumps after skin prick or patch testing
- Bruising or discomfort from blood tests
- A positive result that does not match your symptoms, risking unnecessary avoidance
- A negative result that does not fully rule out a trigger (false reassurance)
- Skin irritation or a delayed reaction at patch test sites
- Needing repeat or additional tests to reach an answer
- Incidental findings on immune tests that lead to more investigation
- A significant allergic reaction during skin prick testing or, more relevantly, during a supervised challenge test
- Anxiety or restrictive diets driven by misinterpreted results
The main risk is misinterpretation. Sensitisation on a skin prick or IgE test is not the same as clinical allergy, and people with high total IgE or other allergies can get spurious positives. Untargeted 'allergy screens' and commercial tests (such as IgG food panels, hair or bioresonance testing) are not validated and can lead to harmful, unnecessary avoidance. Ask how each result will change your plan and whether a test is actually needed.
Published figures to discuss
Headline accuracy figures vary so much by test, trigger and population that single percentages are misleading. Skin prick and specific IgE tests can be falsely positive (sensitisation without allergy) and occasionally falsely negative. Rather than quote invented numbers, this guide stresses the principle: results only mean something alongside a clinical history, and a specialist weighs the chance of false positives and negatives for your specific situation.
| Figure | Reported range | How to interpret it | Source / confidence |
|---|---|---|---|
| Positive allergy test without clinical allergy | Common when broad panels are used | A test result only matters when it matches a convincing history. | Guide sourcesClinical context |
| Normal immune screening despite real recurrent infections | Possible | Some immune problems require vaccine-response testing, repeat immunoglobulins or specialist interpretation. | NHS — Allergy testing and diagnosisnhs.ukSource-linked context |
| Incidental low-level antibody abnormality | Common | Mild isolated abnormalities should usually be repeated and interpreted with symptoms, medicines and infection history. | NHS — Allergy testing and diagnosisnhs.ukSource-linked context |
| Systemic reaction during skin testing | Rare | Skin testing should be performed where staff can recognise and treat anaphylaxis. | Guide sourcesClinical context |
These are literature figures, not a personalised prediction. Your own risks and likely benefits depend on your circumstances, your health, and how your care is carried out and followed up.
What happens afterwards
There is usually no physical recovery from testing. 'Afterwards' is about understanding your results, what they mean for your daily life, and any plan or follow-up.
- Short-lived itching or bumps where skin prick or patch tests were done
- A bruise at the blood test site
- Mild skin redness at patch test sites for a day or two
- Waiting for blood results before a full picture emerges
- Some uncertainty if results are borderline
Aftercare
- Follow the specialist's advice on what to avoid and what is safe — based on the whole picture, not one test.
- If a serious allergy is confirmed, carry any prescribed adrenaline auto-injector and know how to use it.
- Do not start or stop avoiding a food or medicine on the basis of a single result without specialist advice.
- Watch patch test sites for delayed reactions and report any that are severe.
- Keep your test results and any emergency plan accessible.
- Attend follow-up so results can be explained and acted on.
- Be cautious of online or commercial 'allergy tests' that contradict your specialist's advice.
- Symptom and trigger diary written down
- Medicines and supplement list ready
- Antihistamine-stopping advice checked before skin testing
- Previous results and hospital letters gathered
- Packaging or photos of suspected triggers kept
- Several visits planned if patch testing
- Questions for the specialist noted
⚠ Get urgent help if…
- Difficulty breathing, wheeze or noisy breathing after exposure to a trigger
- Swelling of the lips, tongue, throat or face
- Sudden faintness, collapse or feeling very unwell
- A widespread rash or hives with any of the above
- A severe or spreading skin reaction at patch test sites
- Recurrent or severe infections, if being investigated for an immune problem, that suddenly worsen
Who to contact: your clinician, clinic or test provider first (keep their number to hand). For urgent advice when you can't reach them, call NHS 111. In an emergency, call 999.
General guidance — it doesn't replace the specific advice your specialist gives you.
Results & realistic expectations
A good result is a clearer answer to your question — whether an allergy or immune problem is likely, what is safe, and what plan to follow. Sometimes the result rules a cause in; often, just as usefully, it rules one out and prevents unnecessary avoidance.
No allergy or immune test is perfect. A positive test does not prove a trigger is causing your symptoms, and a negative test does not always exclude a problem. The value is in better, safer decisions interpreted by a specialist — not in a single number.
Allergy and immune findings can change over time. Some childhood allergies are outgrown, new ones can develop, and immune test results can shift with health or treatment. Results are a snapshot, and may need repeating if your symptoms change or new questions arise.
Related tests, treatments or support
Several tests are often used together because each answers a different question — for example skin prick and specific IgE for immediate allergy, patch testing for contact allergy, and immune blood tests for infection-related concerns. Where an immune deficiency is suspected, results may be combined with vaccine-response testing and specialist immunology review.
Follow-up & long-term care
Results are usually explained at a follow-up appointment or in a clinic letter, with a clear plan for what to avoid, what is safe, and any treatment or monitoring. Where an allergy or immune condition is confirmed, you should have a named route for questions, repeat testing if needed, and onward referral where appropriate.
- Repeat testing only when clinically useful, not routinely
- Review allergy status if symptoms change or a childhood allergy may be outgrown
- Replace adrenaline auto-injectors before expiry if prescribed
- Keep immune monitoring up to date if an immune condition is found
Repeat, follow-on and what comes next
- Borderline or conflicting results may need repeat or additional testing on another day.
- A supervised challenge test may be needed to settle uncertainty between tests and symptoms.
- Allergy and immune status can change, so results may need revisiting over time.
Ask what happens if the result is unclear or needs repeating, and what is included if further tests or follow-up are needed.
What good aftercare looks like
- A clear, written explanation of results and what they mean for daily life.
- A management plan covering what to avoid, what is safe, and any treatment.
- An emergency action plan and adrenaline training where a serious allergy is confirmed.
- A named contact for questions and a plan for repeat testing if needed.
- Honest advice when testing is not the answer, and onward referral where appropriate.
What affects the cost
Costs vary a great deal between people and providers, and we don't publish prices. What matters is understanding what drives the cost and making sure your quote is complete. The main things that affect it:
- Length and complexity of the specialist appointment
- Number and type of tests (skin prick, specific IgE, patch, immune blood tests)
- Laboratory fees, especially for component-resolved or specialised immune tests
- Whether a supervised challenge test in hospital is needed
- Multiple visits required for patch testing
- Follow-up appointments, written reports and management plans
- Any treatment, adrenaline auto-injector or onward referral arising from the results
- The specialist (allergist or clinical immunologist) consultation fee
- Which tests are included and the laboratory fee for each
- Whether patch testing requires several separate visits
- Whether a supervised challenge test and its hospital costs may be needed
- Follow-up appointment and written results or plan
- What happens, and what it costs, if results are inconclusive and more tests are needed
- Cancellation policy
On the NHS? Allergy and immunology tests are available on the NHS when clinically indicated; private clinics are sometimes used for speed, choice or a second opinion.
You're entitled to your total cost in writing — including reports, follow-up and what happens if the result is inconclusive — before you decide.
Consent traps and marketing red flags
These are not small details. They are often where patients lose choice, time to reflect, or realistic expectations.
Consent traps
- Ordering broad panels and treating every positive as a real allergy.
- Not explaining the difference between sensitisation and clinical allergy.
- Recommending major dietary or medicine avoidance on a single unconfirmed result.
- Using or endorsing unvalidated commercial tests.
- No written plan explaining what is safe, what to avoid, and what to do in an emergency.
Marketing red flags
- Claims that one blood test or panel can 'find all your allergies' or 'intolerances'.
- Selling restrictive diets based on IgG or 'intolerance' testing.
- Promising to 'cure' allergy through testing alone.
- Direct-to-consumer kits that bypass any clinical interpretation.
Choosing a specialist safely
- Check the specialist is on the GMC Specialist Register for this area.
- Make sure they work at a CQC-registered service, and look for membership of the relevant Royal College or professional body.
- You're entitled to time to consider and to have your questions answered before you agree — the specialist who looks after you should explain it, not a salesperson.
- Be wary of pressure: time-limited offers or deposits taken before you've had time to think are red flags, not bargains.
- You're entitled to your total cost in writing — including any follow-up — before you decide.
Questions to ask your medical professional
Take this to your consultation. A good specialist will welcome every one of these.
- Which test is right for my symptoms, and what question is it answering?
- What will a positive or negative result actually change for me?
- Could a positive result be sensitisation rather than a true allergy?
- Do I need to stop any medicines before testing?
- What happens if the results are borderline or inconclusive?
- Will I get a written plan explaining what to avoid and what is safe?
- Is a commercial or home allergy test I have had reliable?
- Are you on the GMC Specialist Register for this area, and which Royal College or professional body are you a member of?
- Will you be the specialist who carries out my test, and who looks after me afterwards?
- What are the risks for someone like me, and how often do your own patients have a problem or need it repeated or redone?
- What does a realistic result look like — and what can this test not achieve?
- What are my options, including waiting, doing nothing for now, or choosing a different approach?
- Can I have written information, results and aftercare instructions in a format I can use, including any accessibility or communication support I need?
- What is the total cost in writing, including any follow-ups, and how much time do I have to decide?
Frequently asked questions
Can I get allergy or immunology testing on the NHS?
Does a positive test mean I'm allergic?
Are home or high-street 'allergy tests' reliable?
Do I need to stop my antihistamines first?
Is the testing painful?
Why might I be referred for immune testing rather than allergy testing?
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How we made this page
Medically reviewed by a GMC-registered consultant. Written in plain English, checked against NHS, NICE, GMC and relevant Royal College / specialist-society guidance, and kept under review. No clinic paid to appear on this page, and we publish no pricing. This is general information to help you prepare — it is not a substitute for advice from your own clinician. How we review our guides →
Source hierarchy: UK regulator and NHS/NICE guidance first, then relevant Royal College or specialist-society guidance, then peer-reviewed evidence for procedure-specific figures where available.
Sources & standards: NHS — Allergy testing and diagnosis BSACI — Skin prick tests and specific IgE tests BSACI — Allergy investigations overview NICE CG183 — Drug allergy: diagnosis and management NICE CG116 — Food allergy in under 19s: assessment and diagnosis UK Primary Immunodeficiency Network (UKPIN)
Reviews reflect patients' experience of care, not clinical outcomes. For procedure volumes and outcome data see PHIN.
Last medically reviewed 2026-09-21. Spotted something wrong or out of date? Report an error in this guide.
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