Positive allergen specific IgE (sIgE) tests represent sensitization and not necessarily clinical allergy. This means that IgE against specific allergens may be detectable even when a patient is clinically tolerant of a given food or environmental allergen. The positive predictive value (PPV) of this testing is low unless the specific allergen tests are carefully chosen based on a review of the patient’s clinical history correlated to specific food and/or environmental exposures. Screening panels and indiscriminate batteries of specific allergen tests should be avoided. Positive specific allergen test results in the absence of clinical allergy lead to incorrect diagnosis of allergy, unsuitable treatment and, in the case of food allergies, inappropriate dietary restrictions with potentially negative health consequences.
Sources:
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Kapur S, et al. Atopic dermatitis. Allergy Asthma Clin Immunol. 2018;14(Suppl 2):43-52. PMID: 30275844.
Muraro A, et al. EAACI Food Allergy and Anaphylaxis Guidelines: diagnosis and management of food allergy. Allergy. 2014;69(8):1008-25. PMID: 24909706.
NIAID-Sponsored Expert Panel, et al. Guidelines for the diagnosis and management of food allergy in the United States: report of the NIAID-sponsored expert panel. J Allergy Clin Immunol. 2010;126(Suppl 6):S1-58. PMID: 21134576.