The clinical significance of serum acid phosphatase

The history of the development of tests for serum acid phosphatase and of the use of such tests in the diagnosis and treatment of patients with prostatic carcinoma is reviewed. Most of the early work is found to be reliable when evaluated in the light of subsequent experience. The properties of the acid phosphatases originating in various organs and the methods of distinguishing between them are discussed. The evidence cited indicates that it is possible to distinguish fairly clearly between the acid phosphatase of the prostate and that of the erythrocytes, but differences between prostatic phosphatase and the acid phosphatase from some other sources appear to be less clear-cut. The theoretical basis of several methods for the determination of serum acid phosphatase is outlined. Evidence is cited which indicates that men with normal prostates and also women may show elevations in serum acid phosphatase if they suffer from disease of any one of several organs. The incidence of such elevations varies with the experimental method, and is less frequent when β-glycerophosphate is used as substrate than when some other substrates are employed. Suggestions are made as to methods by which the origin of this enzyme activity might be clarified. Evidence is also cited which indicates that the possibility of the spontaneous transitory appearance of prostatic acid phosphatase in the serum of normal men should be considered in evaluating the significance of serum acid phosphatase readings.