Evaluation of serum specific IgE for the diagnosis of allergic rhinitis with multi-allergens

Background Objective evaluation of allergic rhinitis (AR) requires in vivo and in vitro tests. In vitro tests are important to assist or ensure the main allergens in multi-allergen-sensitive patients. The aim of this study was to evaluate the utility of serum specific IgE (sIgE) in the diagnosis of AR patients with multi-allergens in the Chinese population. Methods Combining a positive skin prick test (SPT) and clinical history as the diagnostic reference criteria of AR, we estimated concentrations of sIgE produced in response to the 7 most frequent allergens among 85 AR patients, using the UniCAP assay system. Results Among 85 individuals with positive SPT results and allergen-specific nasal symptoms, sIgE concentration correlated well with SPT classes among all the tested allergens. Based on a clinical diagnosis and SPT results using a positive cut-off value of a class 1 score, the CAP test performed well and the sensitivity for different allergens ranged from 0.5 (giant ragweed) to 0.91 (Dermatophagoides pteronyssinus (Der p) and Dermatophagoides farinae (Der f), while specificity ranged from 0.93 (Der f) to 1.0 (animal hair, Der p and mugwort). When the cut-off score was adjusted to class 2, the sensitivity showed an increase overall while the remaining assessed items, including specificity, positive predictive value, negative predictive value and efficiency, showed an unacceptable decline. Conclusions Well-established serum sIgE tests correlated well with SPTs. Setting a class 1 cut-off for positivity of SPT results was better than a class 2 setting for assessing the AR diagnostic value. Chin Med J 2010;123(20):2836-2841