Counterimmunoelectrophoretic studies of serum prostatic acid phosphatase

A counterimmunoelectrophoretic (CIEP) assay for the specific determination of prostatic acid phosphatase (PAP) is described. PAP was obtained from benign human prostatic tissue and a specific antiserum to this enzyme was produced in rabbits and goats. The lowest detectable activity of PAP was at 0.3 IU/l or 4 ng./0.1 ml. This CIEP method was compared to a standard biochemical method (Roy) on a wide spectrum of prostatic and nonprostatic disease. Nonprostatic malignancies and other disorders associated with hyperacidphosphatasemia by the biochemical method were found to be nonreactive for PAP by CIEP. Patients under treatment with various stages of prostatic carcinoma showed comparable elevations by both methods (35%). In untreated patients, the CIEP was statistically most sensitive in stage A (39% by CIEP and 14% by chemical).