500 patients from the South-Western region of Ukraine with suspected or clinically confirmed diagnosis of allergic rhinitis, conjunctivitis, bronchial asthma, pollinosis were examined for the presence of IgE antibodies to 28 allergens by immunoblotting manufactured by Mediwiss (Germany). It was shown that (21.10±2.00)% of the examined patients with antibodies to various allergens have also antibodies to the CСD-marker present on the blot. Such patients significantly changed the epidemiological pattern of sensitization of the examined cohort due to increase of the percentage of positive reactions to plant, insect allergens, and also to latex. The use of CСD-blocker in the re-examination of 84 patients with multiple sensitization significantly reduced the percentage of positive reactions particularly to the allergens containing cross-reactive carbohydrate chains. This makes it possible to recommend the use of CCD-blocker for the elimination of cross-nonspecific reactions during the routine examination of patients with allergic diseases. The possibility of non-specific reactions in the epidemiological analysis of seropositivity to allergens in the population should also be taken into account.