Prostatic acid phosphatase: comparison of radioimmunoassay and enzyme activity assay

Aspects of the clinical use of an enzymatic assay and a double antibody radioimmunoassay for prostatic acid phosphatase are compared. Standard blood sample collection and transport did not have a negative effect on the results of either assay. Our results show no substantial advantage in the use of a radioimmunoassay but emphasize the reliability of the enzymatic assay using alpha-naphthylphosphate as a substrate with respect to its predictive value and specificity in diagnosis and followup of patients with prostatic carcinoma.