The PSA test is a blood examination used primarily for prostate cancer screening. The prostate-specific antigen (PSA) - Total, Free PSA and their ratio in your blood is determined by this test. Both malignant and non-cancerous tissue in the prostate produce PSA. PSA often circulates in the blood in small levels. High PSA levels may be a sign of prostate cancer. However, PSA levels also rise as a result of numerous other disorders such as an enlarged or inflammatory prostate.