Prostate Acid Phosphatase Test - Prostatic Acid Phosphatase (PAP) Test

The prostate acid phosphatase (PAP) test is a quantitative measurement of the level of the acid phosphatase enzyme, primarily produced by prostate gland cells, in the blood serum. Although its levels are elevated in prostate cancer, especially when it has spread beyond the gland (bone metastases), its sensitivity and specificity are much lower than those of the prostate-specific antigen (PSA) test. As a result, PSA tests have largely replaced it in the screening and diagnosis of prostate cancer.