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's correlation between the data set of both methods for a ≥ 0.1 kU/L cut-off was 0.84 (p < .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 µl of sample per test appears to be robust and reliable and can, therefore, be used as an aid in allergy diagnosis.