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Blood Testing for Allergies

Blood tests for allergies are sometimes performed to find out what triggers an allergic reaction and are often used if a patient has a skin condition or is taking medications, such as antihistamines. Such medications can interfere with an allergy skin test, which is a common test used to identify allergy triggers, but in general do not interfere with allergy blood tests. However, there are disadvantages to each test which should be discussed with your health care provider.

The specific IgE (or sIgE) test and the enzyme-linked immunosorbent assay (ELISA) test detect specific antibodies to allergens and are most commonly used to diagnose allergies. In both, a small amount of blood is taken and analyzed for IgE antibodies (allergic antibodies) to specific antigens. 

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These blood tests may not be as sensitive nor as specific as skin testing and tend to be more expensive, but can be useful in some situations. 

WebMD Medical Reference

Reviewed by Luqman Seidu, MD on May 18, 2014

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