Prostate Screening (PSA)

About this test

This test measures prostate-specific antigen (PSA) — a protein produced by prostate cells — in the blood. PSA testing is the standard blood test used to help detect prostate cancer early, when it's most treatable, and to monitor men who have been treated for prostate cancer.

PSA levels are naturally higher in older men and in men with larger prostates. An elevated PSA does not automatically mean cancer — it can also be caused by a benign enlarged prostate (BPH), prostate inflammation (prostatitis), or recent sexual activity. Your clinician will use your PSA trend over time, age, and other factors to decide whether further evaluation is needed.

Components

• PSA Total: Measures all PSA in the blood — both bound to proteins and free. This is the standard screening value.
• PSA Free: Measures only the PSA that is not bound to proteins. The ratio of free to total PSA helps distinguish between cancer (where the free fraction tends to be lower) and benign prostate conditions (where the free fraction tends to be higher). This ratio is particularly useful when total PSA is in the borderline range (4–10 ng/mL).

Who is this test for?

The American Cancer Society recommends that men at average risk discuss PSA screening with their doctor starting at age 50, and that men at higher risk — including African American men and those with a first-degree relative diagnosed with prostate cancer before age 65 — have that conversation starting at age 40–45. This test is also used to monitor men who have already been treated for prostate cancer to check for signs of recurrence.