Allergy testing helps your doctor to confirm which allergens are causing your allergy or asthma symptoms. This allows your doctor to advise suitable treatment options and how to avoid or minimise exposure to allergens that cause symptoms.
Allergy testing using skin prick tests or blood tests measure allergen specific Immunoglobulin E (IgE) antibodies. A positive result means that you are sensitive to an allergen. Results cannot be used on their own and should be considered together with your history of symptoms.
Allergy testing is usually performed on people with allergic rhinitis (hay fever), asthma or allergic reactions to insects, foods or drugs (medications). In people with allergic rhinitis or asthma, allergy tests will usually include dust mites, animal danders, moulds, pollen from relevant grasses, weeds or trees and in some cases, occupational allergens.
Skin prick testing should be supervised by a doctor who is trained to select allergens, interpret results and treat an allergic reaction if it occurs. The tests are usually performed on the patient’s forearm or the back. A small itchy lump (wheal) and red flare will appear within 15-20 minutes for a positive allergy test.
Blood tests for allergen specific IgE antibodies (formerly known as RAST) can be performed when skin prick testing is not easily available, when a patient has severe eczema or when medications such as antihistamines have been taken, that affect skin prick testing results. Measurements of total IgE antibodies can also be measured from a blood sample, but this is not routinely recommended in allergy testing.
Oral allergen challenge testing may sometimes be required for food or drug (medication) allergy to confirm or exclude the cause of a severe allergic reaction (anaphylaxis). These tests should only be performed in carefully selected patients under the supervision of a clinical immunology/allergy specialist in a facility with immediate access to emergency treatment for anaphylaxis.
Patch testing is useful to test for allergic contact dermatitis, that is triggered by substances such as metals, cosmetic preservatives or various plants. Patch tests are usually performed on the patient’s back, and supervised by a doctor who is trained to select allergens and interpret results.
There are several methods that claim to test for allergy, but are unproven. These include cytotoxic food testing, kinesiology, Vega testing, electrodermal testing, pulse testing, reflexology and hair analysis. These tests have not been scientifically validated and may lead to unnecessary, costly and (in the case of some changes in diet) dangerous avoidance strategies. Use of these methods is therefore not recommended.
For more information visit www.allergy.org.au/patients/allergy-testing
© ASCIA 2018
ASCIA is the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand
Postal address: PO Box 450 Balgowlah NSW 2093 Australia
This document has been developed and peer reviewed by ASCIA members and is based on expert opinion and the available published literature at the time of review. Information contained in this document is not intended to replace medical advice and any questions regarding a medical diagnosis or treatment should be directed to a medical practitioner. Development of this document is not funded by any commercial sources and is not influenced by commercial organisations.
Content updated October 2018