Glossary Term:


percent-free PSA


or<b> fPSA</b>


a test that shows how much prostate-specific antigen (PSA) circulates unattached to blood proteins (alone) in the blood. The percent-free PSA (fPSA) is the ratio of how much PSA circulates free compared to the total PSA level. The percentage of free PSA is lower in men who have prostate cancer than in men who do not. A low fPSA may suggest the need for a biopsy. Also known as free-PSA ratio. See also biopsy, complexed PSA, prostate, prostate-specific antigen.