CLINICAL-EFFICIENCY OF IN-VITRO AND IN-VIVO TESTS FOR ALLERGIC DISEASES

Background: Specific serum IgE determination is widely used in the dia gnosis of IgE-mediated allergic diseases but the relative merits of in vitro measurement of IgE antibody in comparison to in vivo skin tests are still debated. Objective: The aim of this study was to investigat e the clinical efficiency of a ''second generation'' technique for in vitro analysis of IgE antibody (Pharmacia CAP System). Methods: Eighty -six patients with suspected inhalant and/or food allergies and 20 asy mptomatic subjects for a total of 655 tests were evaluated. Sera with divergent results between in vitro and in vivo techniques were further analyzed by using ImmunoCAP inhibition and immunoblotting. For the ca lculation of sensitivity and specificity of both in vitro and in vivo tests we considered as true value (reference value) either the concord ant results or, in case of discordance, the datum confirmed by ImmunoC AP inhibition or immunoblot (ie, vitro positive, vivo negative, Immuno CAP inhibition positive; true result: positive). Results: The obtained results demonstrate that the in vitro results correlate well in terms of specificity and sensitivity to this new reference standard. In par ticular a higher specificity for Pharmacia CAP System in comparison to in vivo skin prick test for grass pollens and a better sensitivity fo r mites and cat allergens were found. Conclusions: Our results suggest that the in vitro ''second generation'' testing provides reliable res ults in all clinical situations.