Allergy testing

Injury	Disease	Nutrition	Poison

Symptoms	Surgery	Test	Special Topic

RAST test

Allergy skin prick or scratch test

Intradermal allergy test reactions

Skin testing, PPD (R arm) and Candida (L)

Overview

Risks

Results

Allergy testing

Alternative Names:

Patch tests - allergy; Scratch tests - allergy; Skin tests - allergy; RAST test

What the risks are:

Skin tests and food allergy tests carry a risk that you will experience an allergic reaction when exposed to the allergens. Some sensitive persons will (rarely) experience a life-threatening anaphylactic reaction.

Penicillin and closely related medications are the only drugs that can be tested using skin tests. Skin tests for other drugs are at best non-informative and can be dangerous.

Tests that are not proven as valid include cytotoxic testing, in which foods are mixed in a test tube with a sample of the person's blood and then the white blood cells are observed for a change in shape. Another unproven testing method is "provocation and neutralization" testing, in which the person is injected with a food or other substance and, if there is an allergic reaction, are injected with more of the substance to "neutralize" the response. This can be very dangerous!.

Special considerations:

The accuracy of allergy testing varies quite a bit. Even the same test performed at different times on a person may give different results. A person may react to a substance during testing, but never react during normal exposure. A person may also have a negative allergy test and yet still be allergic to the substance.

Review Date: 8/3/2005
Reviewed By: Frederic F. Little, M.D., Department of Allergy and Pulmonary/Critical Care Medicine, Boston University School of Medicine, Boston, MA. Review provided by VeriMed Healthcare Network.

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