Alternative to In Vivo Tests During the COVID-19 Pandemic: Multiple Allergen Simultaneous Tests as a Useful First Screening

Background: In allergy diagnosis we sometimes find some clinical or logistic limitations to be able to carry out in vivo tests, so the detection of serum allergic-specific IgE could be an alternative as a first screening step. Here, we compare the results from the routine diagnostic tools and multiple allergen simultaneous tests to detect inhalant allergen sensitization. Methods: Thirty-two subjects with a positive ImmunoCAP Phadiatop screening were included, evaluating the accuracy of their diagnosis using (1) specific IgE determination by ImmunoCAP and (2) MAST EUROLINE Immunoblot. Results: The MAST method showed a high agreement and correlation with the ImmunoCAP system for Dermatophagoides pteronyssinus, cat dander, orchard grass and Alternaria alternata. Of the subjects, 94% were sensitized to at least one of the allergens using MAST EUROLINE immunoblot, whereas 79% of individuals with a positive Phadiatop went undetected when we analyzed only the 4 allergens mentioned before. Conclusions: The study showed the usefulness of MAST EUROLINE immunoblot for screening detection of specific IgE antibodies directed against a broad spectrum of inhalant allergens as a first screening tool. Furthermore, its performance is not affected by the possible in vivo test limitations and avoids the arbitrary selection of allergenic sources for evaluation, which may lead to incorrect patients' diagnosis and management.