Prostate Blood Test

• Free PSA
• Total PSA
• %Free PSA

What Tests Can Detect Prostate Cancer Early?

The tests discussed below are used to look for warning signs of prostate cancer. But these early detection tests can’t tell for sure if you have cancer. If the result of one of these tests is abnormal, you will probably need a prostate biopsy to determine if you have cancer.

Prostate-specific antigen (PSA) blood test

Prostate-specific antigen (PSA) is a substance made by cells in the prostate gland (both normal cells and cancer cells). PSA is mostly found in semen, but a small amount is also found in the blood.

Most men without prostate cancer have PSA levels under 4 nanograms per milliliter (ng/mL) of blood. The chance of having prostate cancer goes up as the PSA level goes up.

When prostate cancer develops, the PSA level usually goes above 4. Still, a level below 4 does not guarantee that a man doesn’t have cancer. About 15% of men with a PSA below 4 will have prostate cancer on a biopsy.

Men with a PSA level between 4 and 10 have about a 1 in 4 chance of having prostate cancer. If the PSA is more than 10, the chance of having prostate cancer is over 50%.

If your PSA level is high, your doctor may advise either waiting a while and repeating the test, or getting a prostate biopsy to find out if you have cancer. When considering whether to do a prostate biopsy to look for cancer, not all doctors use the same PSA cutoff point. Some may advise it if the PSA is 4 or higher, while others might recommend it starting at a lower level, such as 2.5 or 3. Other factors, such as your age, race, and family history, may affect this decision.