At a glance
Also known as
total PSA; free PSA; complex PSA
Why get tested?
To help detect and to monitor prostate cancer
When to get tested?
If you have symptoms of prostate disease, such as difficulty in passing urine, or passing urine more frequently than usual and at intervals after treatment for prostate cancer.
There is continued debate among experts and national organisations over when and how often to order the PSA test to screen asymptomatic men. The frequency of prostate cancer screening is an individual decision that should be determined through discussion with your doctor.
A blood sample drawn from a vein in the arm
What is being tested?
Blood is being tested for the level of Prostate specific antigen (PSA) it contains. PSA is a produced mainly by cells in the prostate, a small gland that encircles the urethra in males and produces a fluid that makes up part of semen. Most of the PSA that the prostate produces is released into this fluid, but small amounts of it are also released into the bloodstream. PSA exists in two forms in the blood: free (not bound) and complexed (cPSA, bound to other blood proteins). The most frequently used PSA test is the total PSA, which measures the sum of the free PSA and the cPSA in the blood. When a doctor orders a "PSA test," he is referring to a total PSA.
This test is used to help detect and to monitor prostate cancer. It is not a diagnostic test for prostate cancer. It is a good tool but not a perfect one, and currently there is debate on the usefulness of this test for screening men (see When is it requested section below). Elevated levels of PSA are associated with prostate cancer, but they may also be seen with prostatitis and benign prostatic hyperplasia (BPH). Mild to moderately increased concentrations of PSA may be seen in those of African American heritage, and levels tend to increase in all men as they age.
Recent studies have shown that there is still a small risk of prostate cancer, even if blood PSA levels are normal for age. Therefore even a normal blood PSA level does not mean that there is definitely no prostate cancer present.
The only definite way to confirm whether prostate cancer is present or not is by prostate (taking small samples of tissue).
How is the sample collected for testing?
A blood sample is taken by needle from a vein in the arm. You may be advised to avoid ejaculation and vigorous physical activity affecting the prostate, such as bicycle riding, during the two days before the blood test. The sample should also be collected prior to the physician performing a and prior to (or several weeks after) a prostate biopsy.