Diagnose carcinoma of prostate, metastatic; monitor therapy with antineoplastic drugs in prostatic cancer; evaluate possible histiocytosis. Moderate elevations of total acid phosphatase have been observed with malignant invasion of bone, myelocytic leukemia, Paget disease (advanced), hyperparathyroidism with skeletal involvement, Gaucher disease, and Niemann-Pick disease. Spurious elevations may occur in hemolytic disease and impaired kidney function.