"The prostate specific antigen, or PSA, test is a simple blood test used to screen for prostate cancer. It measures the amount of PSA in a mans bloodstream. PSA is a protein produced by the cells of the prostate gland. This measurement, along with other factors, helps your primary care provider determine your relative risk for prostate cancer. M. D. Anderson recommends that beginning at age 50, men with no family history of prostate cancer should begin annual prostate cancer screening exams. African-American men and men with a family history of prostate cancer should begin annual screening exams at age 45. Both a digital rectal exam and a PSA blood test should be performed."