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Commonly ordered serum IgE testing 'not a reliable diagnostic tool'

An evaluation of serum allergen-specific immunoglobulin E testing found that only seven of 89 tests demonstrated clinical usefulness, according to findings published in the Cleveland Clinic Journal of Medicine.

Cheryl K. Lau, PhD, and Christopher Naugler, MD, CCFP, FCFP, FRCPC, both of Calgary Laboratory Services, wrote that the tests, which are commonly ordered, can have detrimental effects.

"Inappropriate use can lead to false-positive results, a situation in which patients may be subjected to unnecessary food avoidance that can result in nutritional deficiencies and decreased quality of life," they wrote. "It can also lead to false-negative results, when life-threatening diagnoses are missed and further excessive downstream testing is required — all leading to negative outcomes for both patients and health care providers."

As part of their assessment, in which they added scores of specificity and sensitivity, Lau and Naugler stated that "serum antigen-specific IgE testing is not a reliable diagnostic tool."

The researchers included a table of the appropriate ways to evaluate the five major allergen groups. They wrote that:

Food allergens should be evaluated by skin-prick testing and serum antigen-specific IgE testing "with caveats."

Inhalant allergens, such as pollen and dust mites, should be evaluated by skin-prick testing.

Drug allergens should be evaluated in one of two ways: skin-prick testing for penicillin and serum antigen-specific IgE testing for other drugs.

Venom allergens should be evaluated by skin-prick testing and serum antigen-specific IgE testing.

Latex allergens should be evaluated by serum antigen-specific IgE testing, which is the only method approved by the FDA.

Additionally, Lau and Naugler noted that the American Academy of Allergy, Asthma & Immunology has joined with the Choosing Wisely campaign to "advocate against indiscriminate IgE testing in evaluating allergy." They wrote that clinical evaluation and diagnosis of allergens should consist of a combination of history and sensible IgE testing.

"The bottom line is we must consider the poor performance of serum allergen-specific IgE tests when diagnosing and treating suspected type I allergies and avoid ordering food allergen IgE panels whenever possible," the researchers concluded. – by Chelsea Frajerman Pardes

Disclosures: Naugler reports performing informatics consulting for Abbott Laboratories.