Comparison Of The Analytical Performance Of The Euroline (R), Immunocap (R), And Immunocap Isac 112 (R) In Vitro Allergen Sige Diagnostic Assays In The Pediatric Arm Of The Dzl All Age Asthma Cohort (Alliance)

Background: Allergen extract-based versus (vs.) molecular allergen component-based sIgE determination assays vary in their diagnostic performance. Methods: The Euroline® (EL) (Euroimmun) immunoblot (37 extracts and components), the ImmunoCAP ISAC 112® (ISAC) (ThermoFisher Scientific, TFS) microarray (112 components) and the ImmunoCAP® (CAP) (TFS) sx1 (8 extracts) and fx5 (6 extracts) panels were tested among 97 children (69 asthmatic and 28 healthy). Results: Prevalence of allergen sensitization (threshold ≥ 0,7 kU/l) was higher based on the CAP assay for all allergens tested except for peanut (more positive cases detected by ISAC) and soy (equal number of positive cases detected by ISAC). Lowest detection rates were associated with EL for all allergens compared. Overall (and HDM) allergen sensitization concordance vs. the CAP demonstrated higher sensitivity of the ISAC and comparable specificity between ISAC and EL. Quantitative (including CAP class) concordance between CAP and EL depicted a higher analytical sensitivity for CAP but also discrepant results (eg high HDM sIgE with CAP and negative with EL). For both aero-and food-allergens there were samples which were positive for a molecular component although negative for the respective extract. Such cases were more abundant when the comparison was vs. EL as compared to CAP. Conclusions: We observed discrepancies in detection rates of allergen sensitization between the applied methods. Such differences are important for atopy screening and monitoring especially in large epidemiological studies.