LPSA | Free Prostate-Specific Antigen

Free Prostate-Specific Antigen (LPSA / fPSA) is a form of protein secreted by the prostate that circulates in the blood unbound to other proteins. This test is performed only together with total PSA (tPSA) to calculate the fPSA / tPSA ratio. This ratio is an important aid in assessing the nature of prostate diseases, helping to distinguish between benign prostatic hyperplasia and prostate cancer.

A low fPSA / tPSA ratio often indicates an increased risk of prostate cancer, while a higher ratio suggests benign prostate enlargement. The test is especially important for patients whose total PSA level is in the "gray zone" – from 4 to 10 ng/ml, where total PSA alone is not a sufficiently accurate indicator.

Test Principle: The level of free PSA is determined by the immunochemiluminescence method from venous blood. After obtaining the fPSA and tPSA values, the percentage fPSA ratio is calculated. Results are presented in ng/ml and % units.

Recommendations:

• It is recommended to perform together with the total PSA test when prostate cancer is suspected.
• Useful for patients with moderate PSA concentration to avoid unnecessary biopsies.
• Prescribed for differentiating benign prostate diseases from oncological processes.
• Performed to monitor prostate condition in men undergoing active surveillance or after treatment.
• It is recommended to fast for at least 12 hours before the test, avoid sexual intercourse, and prostate massage.