QUANTITATIVE STUDIES ON THE ASSAY OF HUMAN SKIN-SENSITIZING ANTIBODIES (REAGINS). I. AN EXAMINATION OF FACTORS AFFECTING THE ACCURACY OF THE PRAUSNITZ-KUESTNER (P-K) TEST.

A quantitative examination of various factors influencing the accuracy of the P—K test was undertaken. The skin site on the back of most recipients tested did not contribute significantly to the variance observed. Coefficients of variation of a single P—K test of the order of 10–20 per cent were frequently demonstrable, for weals exceeding 50 mm2 in area. Linear log(dose)—response relationships were observed below dose levels corresponding to a 1/5 dilution of the sensitizing serum. A ten-fold increase in dose produced an approximately four-fold increase in weal area. Studies of the influence of the timing and siting of allergen-challenge provided a quantitative indication of the rapid and firm attachment of transferred reaginic antibodies to passively sensitized skin sites.