Allergen-specific IgE: comparison between skin prick test and serum assay in real life

IgE assessment is a crucial step in allergy diagnosis. It may be performed by skin prick test (SPT) or serum IgE (sIgE) assay. Therefore, this study compared these two methods in a real-life setting. METHODS: (W19), cypress (T23), and dog (E5), as they are the most common in our geographic area. RESULTS: Using a positive SPT result as the target condition, remarkably high and statistically significant values of AUC, ranging from 0.84 to 0.94, were found. On the basis of the Youden index the following optimal classification threshold values were also computed: D1 = 0.22, E1 = 0.26, W19 = 0.61, T23 = 0.25, E5 = 0.34. These values allowed to define a set of sensitivity/specifity estimates ranging from 0.75 to 0.93 and from 0.83 to 0.93, respectively. CONCLUSIONS: The present study shows that SPT and sIgE are two tests that are rather concordant, but with different sensitivity and specificity distinct for each allergen. In clinical practice, both tests should be used depending on clinical history features and obtained findings.