Comparison of prostatic acid phosphatase assays.

A prospective study compared five different assays for serum prostatic acid phosphatase in the detection of carcinoma of the prostate gland. The assays included two radioimmunoassay procedures, one counterimmunoelectrophoresis procedure, and an enzymatic procedure using alpha-naphthol phosphate substrate with and without sodium tartrate inhibition. The patients' hospital records were reviewed, as were all available surgical histology slides. The patients were divided into four groups: prostatic carcinoma, benign prostatic hypertrophy, other carcinomas (besides prostatic carcinoma), and no related disease states (that would be expected to give elevated acid phosphatase levels). The results were analyzed with respect to sensitivity, specificity, predictive value of a positive result, predictive value of a negative result, and efficiency of the assays.