what is psa?
What does PSA mean â Prostate Specific Antigen. What is PSA? Prostate Specific Antigen PSA, is an enzyme found in the blood produced exclusively by prostate cells. Normal levels of PSA in the blood are small amounts between 0-2.5 ng/ml. Higher than normal levels, greater than 2.5 ng/ml, can be caused by cancer or benign, non-cancerous conditions such as enlarged prostate, prostate inflammation, infection, or trauma.