[Measurements of prostatic acid phosphatase and prostate specific antigen by fully automated enzyme immunoassay...

Analytical and clinical evaluations were made on the measurement of prostatic acid phosphatase (PAP) and prostate specific antigen (PA) by a fully automated enzyme immunoassay system. Results concerning reproducibility, recovery and sensitivity were good. PAP values by this method correlated well with those obtained by radioimmunoassay. PA values by this method were higher than those obtained by other enzyme immunoassays, although the correlation coefficient was high. PAP, PA and gamma-Seminoprotein (gamma-Sm), another prostatic tumor marker, were all poorly correlated to one another. Normal upper value, 2 SD of 720 healthy males was 1.2 ng/ml for PAP, and 3.7 ng/ml for PA. Positive ratios of these tests in 31 patients with prostatic carcinoma were high at advanced stages, and low at early stages. ROC (receiver operating characteristics) curve analysis on patients with prostatic carcinoma and benign prostatic hypertrophy indicated that PAP and PA were more effective than gamma-Sm for the differential diagnosis of prostatic carcinoma, and that the clinical cut off was 2.0 ng/ml for PAP, 7.4 ng/ml for PA and 4.0 ng/ml for gamma-Sm.