Your doctor may be able to diagnose your condition from your history, symptoms, and physical exam. However, allergy testing is also used to pinpoint allergy triggers. You need this information if you're going to take allergy shots to reduce your sensitivity to these triggers and prevent allergic reactions from developing.
There are three kinds of allergy tests:
- allergy skin test
- allergy blood test
- allergy challenge test
Are allergy tests safe?
The allergen extracts used in allergy tests are typically made of allergen proteins. Because they are made to the standards and requirements set by the US Food and Drug Administration, these products are safe.
Are allergy tests reliable?
Allergy skin testing is considered the gold-standard, the best available test for diagnosing environmental allergies. However, allergy testing isn't perfect, and it is possible to have a positive reaction to an allergen in an allergy test but not have allergic reactions to the substance in real life. Also, sometimes allergy tests fail to detect substances to which you are allergic. They do, however, give your allergy specialist important clues to substances that are likely to be causing your allergy symptoms.
Who performs allergy testing?
Only board-certified allergy specialists have been formally trained to administer allergy prick and intradermal skin testing. Since allergy tests can, in rare cases, cause an anaphylactic reaction, it's important to have the tests administered by an allergy specialist and to stay at the specialist's office for at least 30 minutes after testing to ensure you don't have a reaction after leaving. An anaphylactic reaction can be life-threatening.
Tests That Are Not Helpful in Diagnosing Allergies
Some approaches to allergy testing are questionable. The American Academy of Allergy, Asthma, and Immunology and many other medical associations recommend avoiding the tests listed below. That's because they haven't been scientifically proven to work or else they don't work for the diagnosis of allergies. If your doctor suggests any of these tests, get a second opinion.
- Cytotoxicity testing. In these tests, blood samples are placed on a slide next to allergens to see if the blood cells react to the allergens.
- Urine autoinjection. In this procedure, a small amount of your urine is injected under your skin.
- Skin titration. This is also known as the Rinkel method.This is a skin test where small, varying amounts of allergens are placed on the skin.
- Provocation and neutralization testing. Similar to the Rinkel method, this test involves injecting small amounts of food allergens into the skin in varying quantities. Its goal is to determine the lowest dose of the allergen extract needed to suppress, or neutralize, symptoms.
- Sublingual provocation and neutralization testing. In this test, drops of allergens are placed under the tongue.
- IgG4 assay. This is a blood test for specific types of antibodies.
ABOUT THE AUTHOR
Written by Karen Serrano, MD Emergency Medicine resident at the University of Wisconsin-Madison.
Reviewed by Lisa V. Suffian, MD
Instructor of Clinical Pediatrics in the Division of Allergy and Pulmonary Medicine at Saint Louis Children's Hospital, Washington University School of Medicine
Assistant Clinical Professor in the Department of Pediatrics at Cardinal Glennon Children's Hospital, Saint Louis University
Board certified in Allergy and Immunology
Last updated June 2008