In vitro allergy testing

History and physical examination are the first, and most important steps, in the evaluation of a patient suspected of having an allergy. The diagnosis can be confirmed with either skin or serum testing for evidence of immunoglobulin E (IgE)-mediated reactivity.

The recent literature on serum-based testing for the detection and quantitation of allergen specific IgE (sIgE) was reviewed, identifying where available the "best practices" from high level of evidence studies and/or physician organization guidelines.

Current practices for documenting sIgE are detailed, including enzyme-linked immunoassays on conventional extracts (standardized or not), similar on microarrays of highly purified or recombinant allergens, and basophil activation testing.

Serum testing is an equal alternative to skin testing for establishing the presence of IgE-mediated sensitivity and for identifying the allergens involved. Like skin testing, limitations include the availability of fully detailed allergenic extracts, particularly for foods, drugs, and occupational agents, and the possibility of non-IgE mediated issues.