What is percent-free PSA?

PSA stands for prostate specific antigen. It is a protein in the blood and is measured by taking a person’s blood to identify the amount of PSA that is present within the blood. PSA is important to measure once a man gets older because if the level is abnormal, or elevated, it may indicate a number of prostate conditions, including prostate cancer.  


A normal PSA is less than 4.0 ng/mL. If the PSA level is greater, it is more likely that prostate cancer is present. However, there are other conditions that can raise the PSA. Men with a PSA level between 4.0 and 10.0 ng/mL have about a 25 percent chance of having prostate cancer. If the PSA level is greater than 10.0ng/mL, the chance of having prostate cancer is over 50 percent. If you have a high PSA, a doctor will look at other factors such as age, race, and family history, and also rule out any other possible conditions causing the elevated PSA.

A PSA measurement includes testing percent-free PSA. Total PSA is measured too. First, one must understand that most of the PSA protein that is released into the blood attaches itself to other blood proteins. The PSA that does not attach to other blood proteins is called free PSA. When a man has prostate cancer, he will likely have a free PSA level that is lower than normal. Generally, a free PSA result of less than 10 percent free PSA may indicate prostate cancer.

Reasons why your PSA may be elevated:

·         Prostatitis: Prostatitis is an infection or inflammation of the prostate gland.

·         Older age: Men may have a higher PSA level as a result of older age. This can occur even without any condition affecting the prostate.

·         Benign prostatic hyperplasia: BPH is condition in which the prostate becomes enlarged. It is not cancerous. This usually occurs in men as they get older.

·         Certain medications: Medications like male hormones (testosterone) or other medications that increase testosterone levels may increase the PSA level.

·         Urologic procedures: A prostate biopsy or cystoscopy can increase the PSA level. A DRE may also increase the PSA level. The PSA level goes down within a short period of time after having these procedures. Doctors recommend having a PSA test prior to having these procedures.

·         Ejaculation: After a man ejaculates, the PSA level can increase for a short period of time and eventually goes back down again. Doctors usually recommend that men refrain from ejaculating for at least two days prior to having a PSA test.