[The clinical picture is the most important reason to screen for the presence of allergen-specific IgE in children].

The presence of allergen-specific IgE in serum is associated with sensitization, but the clinical relevance depends on the patient's history. It supports the diagnosis of an acute allergic response to inhalation or food allergens. The presence of allergen-specific IgE in the serum is not necessary for the diagnosis of asthma, perennial rhinitis or eczema; since allergen avoidance has no beneficial effect in these chronic allergic diseases, one should be critical about the relevance of testing for allergen-specific serum IgE. Screening tests for the presence of allergen-specific serum IgE are frequently used in children; a screening test consists of either 5 inhalant or 5 food allergens and if the test is positive, the laboratory will determine the specific IgE for each of the 5 allergens present in the test. This carries the risk of over-diagnosis if the clinical indication is not clear-cut. Furthermore, in children sensitized to grass pollen, the panel of inhalation and food allergens present in screening tests may lead to serological cross-reactivity with wheat; this increases the number of positive screening tests for food allergens without having clinical relevance. In conclusion, the use of screening tests for the presence of allergen-specific serum IgE should be looked at critically since it may unnecessarily increase the number of allergen-specific IgE tests.