Abstract e availability of single allergens and their use in microarray technology enables the simultaneous determination of speci c IgE (sIgE) to a multitude of dierent allergens (> 100) in a multiplex proce-dure requiring only minute amounts of serum. is allows extensive individual sensitization pro les to be determined from a single analysis. Combined with a patient‘s medical history, these pro les sim-plify identi cation of cross-reactivity; permit a more accurate estimation of the risk of severe reac-tions; and enable the indication for spec c immu-notherapy to be more precisely established, partic-ularly in cases of polysensitization.