Prostate-particular antigen, or PSA, is a protein delivered by cells of the prostate organ. The PSA test measures the level of PSA in a man's blood. For this test, a blood test is sent to a research center for investigation. The outcomes are typically reported as nanograms of PSA per milliliter (ng/mL) of blood. The blood level of PSA is regularly lifted in men with prostate tumor, and the PSA test was initially endorsed by the FDA in 1986 to screen the movement of prostate growth in men who had as of now been determined to have the malady.