free PSA

free PSA

Urology PSA in the circulation that is unbound to its usual carrier molecules, the protease inhibitors; free PSA is used to distinguish prostate CA from BPH, etc; free PSA levels are measured in Pts with a total PSA level between 4 and 10 ng/mL and nonsuspicious digital rectal examinations; ↑ free PSA indicates a ↓ risk of CA. See Prostate-specific antigen.