An evaluation of a kinetic acid phosphatase method.

The authors have evaluated a new kinetic acid phosphatase method in which the substrate is alpha-naphthyl phosphate. The original claim that this substrate was highly specific for the prostatic isozyme has been strongly challenged. Therefore, large numbers of patients in the following groupings were included in the evaluation: 52 urology clinic patients, 17 patients with uremia, 11 patients with multiple myeloma and 231 patients who had undergone prostatic biopsies. Two hundred seventy of these patients were found to be free of prostatic cancer. Of these, seven had acid phosphatase values above the upper limit of normal. Five of these seven patients had diagnoses of fibromuscular glandular hyperplasia. One was a woman who had multiple myeloma, and one was a uremic patient. Fifteen of 17 patients who had metastatic cancer of the prostate had elevated acid phosphatase activities, whereas one of 24 patients who had cancer of the prostate but no evidence of metastases had an elevated value.