Allergy Tests landing page
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 blood test. 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 prepare a personalised allergy report for you. Please register here if you are interested in this service.
Our allergy tests
- 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- The RAST specific IgE test was used as a method of IgE detection in the past, but has been replaced by more sensitive tests.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 very important tool when there are 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.