Allergy Tests

Harley Street Allergy Testing Centre

We offer a comprehensive range of allergy tests in our UK centre on Harley Street, London, to identify allergies (both immediate and delayed types) in children and adults. Our paediatric doctors also do allergy tests in babies and children.

Allergy tests are painless and usually, don’t cause any discomfort. Some can be done by one of our doctors during a consultation at the Centre, while others need to be sent away to a laboratory.

We also offer a free online screening questionnaire that you can fill in and submit to us. Your answers will be reviewed by one of our allergy specialists to determine whether you would benefit from a home-based ImmunoCAP ISAC blood test (screening test for 112 allergens).

The test kit is posted out to you and you do the blood test at home then post it back to our laboratory.

One of our allergy specialists will then review the results and send allergy results to you and your GP (if you provide details). Please register here if you are interested in this service.

We also offer face to face appointments in our centre with allergy and paediatic allergy consultants, who will discuss results of the ISAC test with you and recommend treatment.

To book an appointment to see our consultants please


What is ‘allergy testing’?

Allergy testing (in contrast with intolerance testing) help to identify if there is sensitisation to a particular protein in food or respiratory allergens.

Intolerance tests that we do are genetic tests that detect predispositions to digestive issues with lactose (milk sugar) and gluten (protein in wheat barley and rye).

How is allergy testing done?

At a clinic, or at your home.

We have a few allergy clinics across the south of England with the main clinic being in central London. You can visit by appointment, or have a home test kit sent to you by filling in our questionnaire.

Are tests safe?

Yes. Very safe.

Is allergy testing painful?

No, but it involves taking a blood sample from a finger prick or a vein.

What does allergy testing feel like?

If it is a blood test, for example, ISAC everything is done in the lab and you just need to supply a blood sample and a fill in the questionnaire with your symptoms.

There are tests that consultant does during an appointment in the clinic, these can cause light discomfort and itchiness that usually lasts 15-20 min, but nothing dramatic to worry about.

Are there side effects?

There are none, tests are very safe and do not cause any problems.

If a sample is taken from a vein a qualifies medical practitioner should do it. Tests from a finger prick can be done by yourself following video instructions.

What does allergy testing check for?

Specialist consultants can test for a selection of more than 600 allergens including food & aeroallergens (mould, pollen, pet dander, house dust mites and foods including peanut allergy, pet allergy, milk allergy).

Consultants can also test for gluten intolerance and lactose intolerance by genetic tests when these tests are indicated.

In our clinic you get access not only to testing, you get professional advice and treatment as well as testing and treatment for hay fever and asthma, skin problems including rashes and swellings, immune conditions, frequent illnesses, frequent herpes – cold sores, chronic tiredness and fatigue related to infection and immunity.

How does allergy testing work? What types of tests are there?

  • The ImmunoCAP Specific IgE blood test is the most comprehensive method of screening, enabling detection of specific antibodies (sIgE) to 112 allergenic components in one test, including airborne allergens, food and stinging insect venoms. The test requires a tiny amount of blood from either a finger prick (which can be collected at home) or from a vein (collected in a hospital or laboratory). We do this test remotely, enabling patients throughout the UK to send samples in a special container straight to the testing laboratory. Our specialist allergy consultants offer a full interpretation of the results, for both adult and paediatric patients.
  • The RAST specific IgE test was used as a method of IgE detection in the past but has been replaced by more sensitive tests. The RAST test detects antibodies (IgE) against various allergens and sensitisation to more than 400 various food and airborne allergens can be tested using this method, one at a time.
  • The patch test (also known as an epicutaneous test) is an allergy test that detects delayed hypersensitivity reactions to chemicals, perfumes, metals and other allergens. This test is useful for allergic contact dermatitis and other conditions where delayed hypersensitivity is suspected. The patch test is done in the clinic with follow-up appointments two days, three days and four days later, at which the skin where the patch test was carried out is examined for signs of a reaction to the allergens.
  • The elimination diet test is used to determine delayed reactions in atopic dermatitis and other conditions where food might be linked to exacerbations. A special food-symptoms diary is used for this test. This test and any reintroduction of eliminated foods should be done under the supervision of an allergy specialist.
  • In the skin prick allergy test (also known as the scratch test), the allergy consultant will apply drops of different allergens from a pre-prepared panel of allergens onto the skin and then prick (scratch) the skin to allow the allergen into the upper layers of the skin. This test can be done during a consultation in the clinic and the results are visible within 10-15 minutes. Any wheals (red, itchy bumps) greater than 3mm indicate a positive response. Interpretation of the results by an allergy specialist is needed to properly interpret the sensitisation profile. Sometimes both a blood test and a skin prick test are used together by allergy specialists to make the right diagnosis.
  • The Prick to Prick test is similar to the skin prick test but, instead of allergens from a commercially available panel, specific fresh or cooked food is used to diagnose allergic reactions to food. This is a very important tool when there is no commercial extract available or other allergy testing results are negative in the presence of a clear history of reaction to food.
  • The Intra-dermal test is used to detect reactions to medications or other allergens. Small amounts of graded dilutions of the suspected allergen are injected into the upper layers of the skin and the reaction is measured. This method is used usually after skin prick testing.
  • The Ocular conjunctival provocation test is used to evaluate the progress of desensitisation treatment. Dilutions of allergens are placed behind the eyelid in increasing concentrations until a slight redness is observed. This determines the threshold at which a reaction occurs or gives a negative result if the highest concentration has been reached without a reaction.
  • Nasal provocation tests are used to confirm an allergy to a specific allergen when other tests have given uncertain results and doctors suspect that local not systemic antibody (IgE) production is responsible for the symptoms.
  • In the food provocation test or oral food challenge, increased concentrations of a suspected food are given. The first step involves just holding the food in the mouth and then spitting it out. The next step is eating a very small amount of that food. The amount eaten is then gradually increased to determine how much of that food can be tolerated. This test may be done blinded (where the person being tested doesn’t know what they’re eating) or unblinded. Please note, this test must only be done in a hospital where resuscitation equipment and trained staff are available and should never be done at home.
  • The Aspirin challenge (Provocation) test can be done in nasal or oral form in a specific group of patients with asthma who are candidates for aspirin desensitisation treatment.
  • The Drug allergen challenge test is used to exclude allergies to medication (e.g. penicillin or local and general anaesthetics). This test is done in the hospital under the observation of trained staff and consists of several stages of skin prick tests, intradermal tests, provocation tests. It can last many hours and in some cases patients will need to stay in the hospital overnight. Where a reaction to multiple drugs is suspected, several visits may be needed.

Which type of doctor does the testing?

Our paediatric doctors perform allergy tests in babies and young children.

We have colleagues in different specialities who are working with us including:

  • skin specialists (dermatologists)
  • stomach specialist (gastroenterologist)
  • blood specialist (haematologist)
  • endocrine specialist
  • immunologist
  • gynaecologist
  • paediatric doctor

What age is suitable to have allergy testing?

Any age.

Parent decide if they are comfortable to take a blood sample from their child (older than 6 years old) there is an option for home self-collection, if not they can find healthcare professional locally who can collect blood drops from a finger or heel prick (for babies) or a vein.

If you wish to travel to our lab in central London a nurse can take a sample Extra charge of £32.50

How often should you be tested for allergies?

Your consultant will recommend how frequently allergy tests are needed.

Usually, in children, we recommend repeating every 3-5 years, more often if the situation changes.

Adults on average every ten years, but can be checked more frequently if needed.

When is allergy testing appropriate or recommended?

The consultant will review the patient’s questionnaire prior to approving the test. This is why our consultants will take a decision prior to authorising the test and will advise if in their opinion the test will be beneficial in the clinical situation or not.

You can still have the test done even if consultant thinks that other tests are required, but you will be advised accordingly you can book an appointment to discuss the problem in clinic if you wish.

The usual criteria for doing allergy tests are in regards to food, and include:

  • a history of rashes
  • swellings
  • feeling sick
  • vomiting
  • diarrhoea within minutes up to 24 hours after eating food, with or without doing exercise
  • exposure to non-steroidal anti-inflammatory drugs (aspirin etc)
  • the heat of sunshine
  • alcohol or combination of those factors above

For hay fever sufferers or asthma sufferers (wheezing, chest tightness, shortness of breath and a cough) – respiratory problems on exposure to allergens or seasonal allergies.

  • problems with eyes, including:
    • itchy, red
    • watering eyes (conjunctivitis) and nose as well as
    • scratchy throat and an itchy, runny or blocked nose (allergic rhinitis).

For intolerance tests (different from allergy tests):

  • bloating,
  • abdominal dilatation after eating wheat, barley or rye (pasta, beer lager etc) for adults and children
  • screening for coeliac disease/gluten intolerance, or milk products containing lactose – (adult type of lactose intolerance) test for lactose intolerance.

We do not usually recommend allergy test in case of recurrent spontaneous rashes (not linked with consumption of food) spontaneous urticaria – raised, itchy, red rash (hives), as well as spontaneous swellings swollen lips, tongue, eyes or face, tummy pain (we advise to book an appointment with allergy consultant and seek advice and treatment, different types of tests will be recommended).

If you get dry, red and cracked skin eczema or dermatitis especially around your mouth or eyes we also recommend to see a consultant as other types of tests that are only done in the clinic might be required.

The symptoms vary depending on what you’re allergic to and how you come into contact with an allergen.

For example, you may have a runny nose if exposed to pollen, develop a rash if you have a skin allergy, or feel sick, get lips or tongue swelling if you eat something you’re allergic to.

In case of severe reaction, you need to seek immediate medical attention and book your appointment or do allergy tests when you get better.

What are the symptoms of a severe allergic reaction to something?

Anaphylaxis is a medical emergency that requires immediate treatment.

If there is difficulty breathing, swelling of the throat and tongue, rapid reaction, drop in blood pressure – feeling faint after contact with an allergen, lightheadedness, confusion, blue skin or lips, collapsing and losing consciousness Anaphylaxis requires immediate treatment and call for help from emergency services.

Which type of allergy testing is most accurate?

The ImmunoCAP ISAC Specific IgE blood test is the most comprehensive method of screening, enabling detection of specific antibodies (sIgE) to 112 allergenic components in one test, including airborne allergens, food and stinging insect venoms.

The test requires a tiny amount of blood from either a finger prick (which can be collected at home) or from a vein (collected in a hospital or laboratory).

We do this test remotely, enabling patients throughout the UK to send samples in a special container straight to the testing laboratory. Our specialist allergy consultants offer a full interpretation of the results, for both adult and paediatric patients.

What affects allergy testing?

Antihistamines. Please make sure that you avoid antihistamines 2 days before any appointment in the clinic though this is not the case if you have severe rashes or swellings.

If you can’t stop antihistamines before your allergy testing appointment in the Allergy Clinic there is a range of other types of allergy tests instead of skin prick test please tell your consultant or e-mail this to our customer support.

Home test finger prick tests have no such restrictions.

Why no antihistamines before testing for allergies?

It is very important that, if possible all antihistamines are stopped at least 2 days before the appointment but NOTE that no such restrictions apply to home testing.

If you are concerned about stopping antihistamines of feel unable to do so please contact our support team by e-mail Antihistamines are often prescribed or recommended for patients with allergic problems.

They include:

  • Chlorphenamine (also called PIRITON)
  • Loratadine (also called CLARITYN)
  • Levocetirizine (also called XYZAL)
  • Acrivastine (also called BENADRYL)
  • Rupatadine (also called RUPAFIN)
  • Cetirizine (also called ZIRTEK)
  • Fexofenadine (also called TELFAST)
  • Desloratadine (also called NEOCLARITYN)
  • Misolastine (also called MIZOLLEN)”

When to postpone testing?

For skin tests, you nee to avoid antihistamines. For blood tests,  there are no restrictions.

Is allergy testing safe while pregnant?

Yes. Very safe.

When to test a child for allergies?

Any age. Self-collection of six, under six sample from a healthcare professional.

How is allergy testing done on infants?

Finger prick collection is not suitable for small children, toddlers and babies.

In these cases, the sample from the child needs to be taken by a trained healthcare professional (our lab can provide the necessary materials on request if you are located at a distance from London), or in London you can attend the lab with our form where the sample will be collected Monday to Friday, 7am-7pm and Saturday 9am-5pm.

Where to get allergy testing done?

We offer a comprehensive range of allergy tests in London or convenient home testing you live elsewhere in the UK.

We have a few allergy clinics across the south of England with the main clinic being in central London.

You can visit by appointment, or have a home test kit sent to you by filling in our questionnaire.

Where to get allergy testing in London?

Our Allergy Consultants in London Harley Street, City of London Allergy Clinic and East London Allergy clinic are always happy to help.

Where to get testing in the UK?

We offer convenient at home allergy testing for patients across the UK in Scotland, England, Wales and Northern Ireland;

Where to buy allergy testing kits?

Complete the online questionnaire and if the consultant decides you would benefit from a blood test, a kit will be sent to your home.

What does allergy testing cost?

Private allergy tests cost £26 per allergen (excluding consultation fee and excluding recombinant allergens)

Are allergy tests covered by insurance?

All our consultants are registered with main private insurance companies.

If you have private insurance consultation and testing costs can be covered partially or in full by your insurance company. Consultation fees, as well as costs of diagnostic procedures in many cases, can be billed to your insurance company directly, but with some policies, you will have to pay in the clinic and can claim reimbursement based on our receipts.

Please contact your company before consultation and obtain authorisation number to see one of our consultants.

Please check if your company if you have an excess on your insurance policy (you will need to pay it during the consultation).

For patients who are willing to fund consultations themselves consultation fee can be paid by debit card, cash or a bank transfer. With some policies, you are required pay for your consultation in the clinic and claim the sum back based on our receipt.

How long will it take to get my results back?

Your personal test report will be ready up to 2 weeks after you send the sample back to the laboratory.

The results will be reviewed by one of our specialist allergy consultants in conjunction with your questionnaire answers.




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