Performance of the PROTIA(TM) Allergy-Q(R) System in the Detection of Allergen-specific IgE: A Comparison With the ImmunoCAP(R) System

ABSTRACT

PURPOSE: The PROTIA(TM) Allergy-Q(R) enzyme immunoassay (EIA) is a recently developed screening assay for specific immunoglobulin E (sIgE) for multiple allergens. The ImmunoCAP(R) fluorescent EIA (FEIA) system is the most widely used method for sIgE detection. In this study, we evaluated the performance of the Allergy-Q(R) system compared to the ImmunoCAP(R) system. METHODS: We compared the 2 systems using sera from 260 Korean allergy patients suffering from asthma (26.5%), allergic rhinitis (42.3%), atopic dermatitis (67.7%), and food allergy (18.1%). We compared sIgE-measurement results for 7 inhalant allergens, 5 food allergens, and 4 microorganism allergens. RESULTS: Overall, 1,799 paired assay results were analyzed. Except mugwort and alternaria, most of the allergen-sIgE results showed intra-class correlation coefficients of >0.5. Inter-assay class associations were reliable for most allergens (gamma=0.858-0.987, P<0.001). Passing-Bablok regression analysis showed multiple differences in intercept and slope. The inter-method concordance was moderate to substantial for most allergens (kappa=0.713-0.898, P<0.001). CONCLUSIONS: The PROTIA(TM) Allergy-Q(R) EIA system exhibited good detection performance compared to the ImmunoCAP(R) FEIA system in Korean allergic patients. However, because of methodological differences between the 2 assays, careful clinical implication is required for the interpretation of Allergy-Q(R) EIA results.