PSA Reflex to Free PSA is a two-step laboratory strategy in which a total PSA result falling within a defined gray zone (typically 4–10 ng/mL) automatically triggers measurement of free (unbound) PSA on the same specimen, with results expressed as a percent free PSA ratio (free PSA ÷ total PSA × 100). This reflex approach improves the specificity of prostate cancer detection without requiring an additional patient visit or blood draw. It is widely used to help distinguish benign prostatic hyperplasia (BPH) from clinically significant prostate cancer in men with intermediate PSA elevations. PSA (prostate-specific antigen, kallikrein-3) is a serine protease secreted by prostatic epithelial cells that circulates in two major forms: complexed PSA (bound primarily to alpha-1-antichymotrypsin) and free PSA (unbound). Prostate cancer cells tend to produce more complexed PSA relative to free PSA, so the percent free PSA is inversely associated with cancer risk—lower percent free PSA correlates with higher probability of malignancy. Benign conditions such as BPH and prostatitis generally produce proportionally more free PSA, yielding a higher percent free PSA ratio.
When your PSA blood test result falls in a middle range, this follow-up test measures how much of the PSA in your blood is 'free' versus attached to other proteins—a lower percentage of free PSA may mean a higher chance of prostate cancer, helping your doctor decide whether a biopsy is needed.
When elevated: A high percent free PSA (≥25%) in the gray zone is associated with a lower probability of prostate cancer and is more consistent with benign prostatic hyperplasia or prostatitis. While reassuring, it does not exclude malignancy, and clinical judgment, DRE findings, and patient risk factors must still guide management. Repeat PSA testing and ongoing surveillance remain appropriate even when percent free PSA is elevated. When low: A low percent free PSA (<10–15%) in the gray zone is associated with a substantially increased probability of prostate cancer and generally supports consideration of prostate biopsy after shared decision-making. This finding should prompt discussion of biopsy risk, patient preferences, and whether additional risk-stratification tools (e.g., MRI, PHI) are warranted. A low percent free PSA alone is not diagnostic of cancer and must be contextualized within the full clinical picture.
PSA reflex testing is not athlete-specific and relates to prostate health screening in men, which is a general health-longevity consideration rather than a performance or training biomarker. Athletes over 40–50 may benefit from PSA monitoring as part of routine preventive care, but this test does not directly inform training decisions, recovery status, or athletic performance.
Turnaround Time
3 days (up to 7 days)
Fasting Required
No
Order online
Choose your lab and check out. We send your lab requisition automatically — no doctor visit needed.
Get your sample collected
Visit a lab service center near you for a quick blood draw (or book at-home phlebotomy where available).
See your results
Your results land in your Insider portal, ready to review and act on — that easy.
Your price
$27.90$70
2.5× less than retail
Versus the typical direct-to-consumer retail price for this test (illustrative — consumer prices vary by provider and region).
$27.90
Peer-reviewed sources supporting the educational content on this page.
