MedicalTerminology DB

Meaning of free PSA: The amount of the protein prostate-specific antigen (PSA) in the blood that is not attached to other proteins.

Definition of free PSA

The amount of the protein prostate-specific antigen (PSA) in the blood that is not attached to other proteins. It is compared with the amount of PSA in the blood that is attached to other proteins. The amount of free PSA is higher in men with benign prostatic hyperplasia (BPH).The amount of PSA attached to other proteins is higher in men with prostate cancer.

Written and maintained by James Murray Last updated July 21, 2026 Educational reference, not medical advice. Read the limitations.

For learning, not diagnosis. This glossary provides general educational information and is not a substitute for advice from a qualified healthcare professional. If you may be experiencing a medical emergency, contact local emergency services.