Diagnostic accuracy of four assays of prostatic acid phosphatase. Comparison using receiver operating characteristic curve analysis
J. L. Carson, J. M. Eisenberg, L. M. Shaw, H. L. Kundel and K. A. Soper
We compared the diagnostic characteristics of four assays of prostatic acid
phosphatase by two methods. In the first analysis, receiver operating
characteristic (ROC) curves were developed and the areas under the curves
were calculated. In the second analysis, the sensitivity of each assay was
compared with the sensitivities of the other assays with specificities set
at equal levels. One or more assays were performed in 1,298 patients; 141
underwent all four assays. Pairwise comparisons of the areas under the ROC
curves showed no significant differences. No differences were found in the
sensitivities of the four assays when the upper limits of normal were
selected to provide equal specificities. We conclude that there is little
difference in diagnostic accuracy among the prostatic acid phosphatase
assays. Our findings contrast with previous studies that used only one
upper limit of normal and that found some assays to be superior to others.
Receiver operating characteristic curve analysis corrects for the bias
introduced by the choice of an upper limit of normal.
