Validation study of a new chemiluminescent singleplex IgE assay in a set of Italian allergic rhinitis patients.

BACKGROUND The measurement of specific IgE to allergenic extracts and molecules in patients with allergic rhinitis (AR) is crucial for a precise diagnosis and further immunotherapy. Companies providing in vitro diagnostic methods in allergology continuously strive for the optimization and modernization of such methods. A new generation of automated allergy tests based on chemiluminescence detection and paramagnetic microparticles is now available, with possible advantages in sample volume, cost-effectiveness, and avoidance of sample-related interference. OBJECTIVES To test whether sIgE antibody levels obtained with a new singleplex chemiluminescent method have a good agreement with the corresponding results obtained with a "gold standard" test. METHODS We tested sera from 368 AR patients. Specific IgE sera levels (kU/L) to a comprehensive panel of 15 allergen extracts and 6 molecules were tested with ImmunoCAP® (Thermo Fisher Scientific Inc., Phadia AB, Uppsala, Sweden) and NOVEOS™ (HYCOR® Biomedical, Garden Grove, CA, USA). We evaluated the qualitative and quantitative performance of the new NOVEOS system in matching the outcome of ImmunoCAP to each of the examined allergens. RESULTS In relation to ImmunoCAP, the overall diagnostic sensitivity and specificity of sIgE tests with NOVEOS were 90.8% (95%CI=88.6-92.7) and 96.2% (95%CI=93.9-97.8), respectively. These values were higher when only molecules were considered (sensitivity=98.7% [95%CI= 96.4-99.7%]; specificity=94.2% [95%CI= 88.4-97.6%]) and lower when only extracts were considered (sensitivity=87.6% [95%CI= 84.7-90.2%]; specificity=97% [95%CI= 94.4-98.6%]). Spearman correlation between the data set of both methods for a ≥0.1 kU/l cutoff was 0.84 (p<0.001). CONCLUSIONS The new singleplex NOVEOS system presented good results for qualitative and quantitative comparisons when testing specific serum IgE antibodies against a range of 21 allergens. This novel immunoassay system using only 4 microliters of sample per test appears to be robust and reliable, and can, therefore, be used as an aid in allergy diagnosis.