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

In a nonallergic person, allergy tests should be negative (no response to the allergen).

A positive result means you reacted to a specific substance. Often, but not always, a positive result means the symptoms that you are having are due to exposure to the substance in question. In general, a stronger response means you are more sensitive to the substance.

People can have a positive response with allergy skin testing, but not have any problems with the specific substance in every day life.

The skin tests are generally reliable. However, if the dose of allergen is excessive, a positive reaction will occur even in persons who are not allergic.

Images

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

Allergy skin prick or scratch test

Intradermal allergy test reactions

RAST test

Review Date: 06/25/2011
Reviewed By: David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc., and Stuart I. Henochowicz, MD, FACP, Associate Clinical Professor of Medicine, Division of Allergy, Immunology, and Rheumatology, Georgetown University Medical School.

A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org)