Clinical applicability of acid phosphatase isoenzyme assay.

We compared electrophoretic evaluation of acid phosphatase isoenzymes with spectrophotometric determination of prostatic acid phosphatase in terms of clinical utility. In all of 33 cases of prostatic carcinoma, an increased prostatic fraction was detected; in nine prostatectomized patients, this fraction returned to normal as measured by either technique. Abnormal spectrophotometric results were also seen in 10 cases of benign prostatic hypertrophy and seven cases of non-prostatic disorders, but only two benign prostatic hypertrophy and one non-prostatic case showed a prostatic band (band 2) in an electrophoretogram. Band 2 was not demonstrated in 463 patients affected by a great variety of diseases but without prostatic disorders. A weak band 5 was seen in patterns for most patients, except for cases with metastatic bone tumor and Gaucher's disease, whose serum showed a strong band 5. The specificity of bands 2 and 5 seems to be confirmed by this large series of patients. Measurement of acid phosphatase isoenzymes is recommended as a routine screening test for patients whose serum acid phosphatase is abnormally high, because the isoenzyme study not only indicates the presence or absence of prostatic cancer but also whether or not there is bony metastasis. Other disorders such as Gaucher's disease, different kinds of leukemias, and thrombocythemia may also be detected and distinguished by this screening technique.