Allergy tests help to identify or confirm what allergens are causing allergy and/or asthma symptoms. Skin prick tests or blood tests measure allergen specific Immunoglobulin E (IgE) antibodies. A positive result indicates sensitivity to an allergen. However, test results cannot be used on their own and should only be considered together with a patient’s history of symptoms.
Allergy test results allow doctors to advise suitable treatment and management options. This includes advice on how to avoid or minimise exposure to allergens that cause symptoms.
Allergy tests are usually performed in people with allergic rhinitis (hay fever), asthma or suspected allergic reactions to insects, foods or drugs (medications) and 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 a patient’s forearm or 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 test results.
Oral allergen challenge tests are sometimes required for food or drug (medication) allergy to confirm or exclude allergy. These tests should only be performed in carefully selected patients under supervision of a clinical immunology/allergy specialist, with access to treatment for severe allergic reactions (anaphylaxis).
Patch tests are used 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 a 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 November 2018