The PSA (prostate-specific Antigen) Test has been widely used to screen men for prostate cancer. Prostate – specific antigen or PSA is a protein produced by cells of the Prostate gland. This test measures the level of PSA is a man’s blood. It is more like a routine blood test, a blood sample is collected and sent to the laboratory for analysis. An yearly PSA Test for men at the ages of 40 is fairly recommended to detect Prostate Cancer.