OPTIMIZATION OF SKIN TESTING .2. EVALUATION OF CONCENTRATION AND CUTOFF VALUES, AS COMPARED WITH RAST AND CLINICAL HISTORY, IN A MULTICENTER STUDY

In this multicenter study we evaluated the results of a previous study (part I) in a relatively large Dutch patient population, using the tw o previously tested allergens (house-dust mite and grass pollen) and t wo other standardized allergens (tree pollen and cat dander). The obta ined skin test results were expressed as a histamine ratio and compare d with RAST and clinical history (CH). The sensitivity and specificity were calculated at different cutoff values of the skin tests. The opt imum cutoff values of 0.7 intracutaneous tests (ICT) and 0.4 skin pric k tests (SPT) resulted in a predictive value for the detection of alle rgic sensitization of 83% (RAST) and 77% (CH), and 91% (RAST) and 86% (CH), for the ICT and SPT, respectively. As the ICT and SPT were perfo rmed in different centers, the results of these methods cannot be comp ared. No systemic side-effects of the skin tests were recorded. These results generally correspond well with the predictions regarding safet y and predictive value of part I of this study, in which a limited num ber of patients was studied. In conclusion, through the use of a limit ed number of standardized allergens in a small group of patients, it m ay be possible to predict a safe and efficacious concentration for rou tine skin testing and to extrapolate from these results to other stand ardized allergens.