Reliability of bone marrow acid phosphatase as a parameter of metastatic prostatic cancer

The reliability of bone marrow acid phosphatase determination by a spectrophotometric assay and 2 immunochemical methods was evaluated in 40 patients: 20 men with known prostatic carcinoma and 20 men of comparable age without clinical evidence of prostatic cancer. The large percentage of falsely positive results obtained by the colorimetric assay invalidates this method as the sole parameter of metastatic prostatic carcinoma.