Ac. Phosphatase
Sample: Serum with Acetic Ac.
Schedule: Daily
Units: U/L
Range: Less than 3.5
Remarks: See also: PSA Acid Phosphatase (ACP) was found to be much more prevalent in male than in female urine. It was soon shown that prostatic tissue contains this enzyme in high concentration. Elevated serum levels of acid phosphatase (ACP) are seen in patients with prostatic carcinoma that has metastasized.
Patients with prostatic carcinoma still confined within the capsule usually have normal serum levels of this enzyme. However, patients with benign prostatic hypertrophy may have slight elevations of the serum ACP level aftervigorous prostatic "massage." Thus, acid phosphatase determination is of utility in diagnosing metastatic carcinoma of the prostate but is of little value in diagnosing resectable prostatic carcinoma.
Because other tissues, such as erythrocytes, may also release acid phosphatase into the serum, minor elevations of enzyme levels may reflect such an origin rather than the prostate. Accordingly, efforts have been made to distinguish "prostatic" ACP from the isoenzymes that are of erythrocyte and other origin. The efforts to distinguish "prostatic" acid phosphatase from erythrocyte acid phosphatase have been based on the differential effect of various substrates and various inhibitors on enzymes from these two sources.
Elevated levels of this enzyme are also frequently seen in metabolic disorders such as Gauchers disease and Niemann-Pick disease. Elevated levels of tartrate-resistant acid phosphatase are found in hairy cell leukemia, an important diagnostic aid for this condition.
Acid phosphatase is present in significant amounts in seminal fluid and has been found useful fo- rensically in the diagnosis of rape because vaginal acid phosphatase activity is low (<10 U/L), whereas postcoitally it reaches values >50 U/L.
