Free PSA
The unbound fraction of PSA — used alongside total PSA to refine cancer risk.
What is it
Free PSA is the portion of PSA not bound to other proteins in circulation. It is used alongside total PSA to refine prostate cancer risk assessment.
Why it's measured
The ratio of free to total PSA has been studied as a refinement tool when total PSA is in an intermediate range.
Reference range
Standard laboratory reference
Context-dependent ng/mL
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
Clinical interpretation depends on total PSA and the free/total ratio.
Lower
Clinical interpretation depends on total PSA and the free/total ratio.
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
Measured when total PSA is elevated to refine risk assessment.
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.