Free PSA
Here’s what it reflects — and what to do about it.
Longetic pulls together every lab and record you’ve had, follows how Free PSA changes over time, and explains what’s shifting — so you walk into your next appointment prepared, with reminders for retests along the way.
What is Free PSA?
The portion of PSA in the blood that is not bound to other proteins, measured as a follow-up when total PSA is elevated.
PSA circulates in two forms, bound to proteins and unbound (free); free PSA measures just the unbound part. It is usually a follow-up test in men whose total PSA is elevated, used to help decide whether a prostate biopsy is worthwhile. On its own the free PSA number means little; it is meaningful mainly as part of the free-to-total ratio (percent-free PSA). Like total PSA, it applies only to men and does not diagnose cancer by itself.
What to know about Free PSA
Understanding Free PSA means knowing what it reflects, what tends to move it, and the signs that suggest it’s worth a closer look — so you can bring the right questions to your next appointment.
This glossary entry is for informational purposes only and is not a substitute for professional medical advice. Read our Medical Disclaimer.
References
About our sources
Official sources
Government health agencies, national institutes, and intergovernmental bodies whose guidelines carry regulatory or policy weight.
Clinical / professional
Medical societies, specialty colleges, and professional associations whose consensus statements reflect clinical practice standards.
Peer-reviewed research
Original research articles and systematic reviews published in indexed journals and verified through PubMed or DOI.