% Free PSA
The percentage of total PSA that is unbound — used to distinguish benign vs. cancer-related elevations.
What is it
The percent free PSA is calculated as free PSA divided by total PSA × 100. Lower percentages have been studied as markers more concerning for prostate cancer.
Why it's measured
Used clinically when total PSA is in the 4–10 ng/mL range to refine biopsy decisions in research literature.
Reference range
Standard laboratory reference
> 25 %
Reference ranges vary by laboratory. Your individual reference range will appear on your test report and should be interpreted by your physician in the context of your overall health profile.
What results may indicate
Elevated
Higher percentages are generally considered more favorable in published research.
Lower
Lower percentages have been associated with elevated prostate cancer risk in research literature.
These associations are general. They are not a personal diagnosis or prediction. Discuss your individual results with your physician in the context of your full health profile.
When it's measured
Calculated when both total and free PSA are measured.
Related markers
Measured in
A complete look at your heart, hormones, metabolism, inflammation, and longevity systems — drawn at Quest or LabCorp, reviewed by a U.S.-licensed physician.
Explore the Apex Panel →This information is for general educational purposes only and is not medical advice. Lab results alone are not intended to diagnose, treat, or cure any condition and do not replace the advice of a healthcare provider. OPTML does not offer medical advice, a diagnosis, medical treatment, or any form of medical opinion.