FACT SHEET

ALLERGY TESTING

Allergy testing can help the more than 50 million Americans who have allergic disease find out which allergens make them sneeze and wheeze and help their allergist develop the most effective treatment plan.

• Allergy tests are performed using either skin tests or blood tests.

• There are two types of skin tests: percutaneous, also known as prick, puncture or scratch tests, and intracutaneous, also known as intradermal, tests. Skin test results are obtained quickly, with positive reactions usually appearing in 15 to 20 minutes.

• The percutaneous tests prick or scratch the surface of the skin, introducing a tiny amount of a suspected allergen. The test is performed on a patient’s back or forearm with multiple allergens tested at once. A positive reaction causes redness and swelling to appear at the site of the scratch.

• Intracutaneous skin tests are sometimes performed if percutaneous test results are inconclusive. This test type involves injecting the suspected allergen extract under the first few layers of skin with a syringe and a very fine needle. Intracutaneous skin tests are more sensitive, and more often positive tests, than percutaneous testing, which also means that they more often yield false positive results.

• Blood tests, once known as radioallergensorbent testing (RAST), often are used to test for allergies when: a physician advises against the discontinuation of medications that can interfere with test results or cause medical complications; a patient suffers from severe skin conditions such as widespread eczema or psoriasis; or a patient has such a high sensitivity level to suspected allergens that any exposure to those allergens could result in potentially serious side effects. Newer testing methods give accurate measures of allergic antibodies.

• Blood tests are conducted by drawing a blood sample to be sent to a competent, certified laboratory, which analyzes the sample for the presence of antibodies to specific allergens. It can take up to several days to receive test results.

• Children and adults of all ages can be tested for allergies.

• Allergy tests can be conducted for most common allergies, including plant pollens, molds, dust mites, animal dander, insect stings, and various foods such as peanuts, eggs, wheat, shellfish and milk. Testing is also available for some drugs, such as penicillin.

The American College of Allergy, Asthma and Immunology (ACAAI) has more information that can help you get your allergies under control.  Call its toll-free number 800-842-7777 or visit www.acaai.org to learn how you can have a life without allergies.