Rapid radioimmunoassay for prostate-specific acid phosphatase in human serum.

We describe a rapid radioimmunoassay for human prostatic acid phosphatase (EC 3.1.3.2) in serum, with use of monospecific antisera raised in rabbits against the primary highly purified acid phosphatase (pl 4.9) from human prostates, and with a second antibody-polyethylene glycol porecipitation. This radioimmunoassay is sensitive and can be performed within 5 h. Concentrations of the immunoreactive acid phosphatase in sera of healthy men (n = 394) ranged from 0.3 to 3.6 microgram/L (mean 1.94, SD 0.66 microgram/L). Concentrations of the enzyme in sera of men with benign prostatic hyperplasia (n = 56) or with carcinoma of nonprostatic origin (n = 24) were identical with those of the reference group. Serum concentrations of immunoreactive prostatic acid phosphatase of patients with occult, non-metastatic, and metastatic prostatic carcinoma varied from 1.7 to 9.3 (n = 9), 4.2 to 59.4 (n = 12), and 20 to 198 (n = 10) microgram/L, respectively. The amount of immunoassayable prostatic acid phosphatase was unchanged for at least five days in serum stored at 4 degrees C.