A screening test to check PSA levels is a commonly used tool in prostate cancer detection, although it is by no means conclusive. The use of this test remains controversial, with many researchers offering evidence that it is not an accurate predictor of prostate cancer. However, the test to check PSA levels may also be used to monitor the effectiveness of prostate cancer treatments. PSA levels that are higher than normal may also indicate prostatitis, a noncancerous condition, or an enlarged prostate. Talk to your doctor about whether you should have your PSA levels tested.
What does PSA mean?
PSA stands for prostate-specific antigen. It is a protein that your prostate gland produces. Most of the PSA is released into your ejaculate, but some of it is also released into your bloodstream. This substance may be complexed (cPSA), which means that it is bound, or it may be free. PSA tests typically check for total levels of PSA.
If your doctor recommends that you undergo a series of PSA tests over a period of time, it means that he is interested in your PSA velocity. This refers to the rate of change of your PSA levels. Along with your total PSA level, your PSA velocity can be used as a tool to detect prostate cancer.
If the PSA level rises rapidly, it may indicate an aggressive cancer. However, a prostate biopsy will be needed to confirm a diagnosis of prostate cancer, as this blood test is not conclusive.
Preparing for the PSA test
There is little preparation required, as this is a simple blood test. However, engaging in certain activities prior to the test can skew the results. Avoid rigorous physical activity, particularly bicycling, before having your blood drawn. Avoid ejaculating for 24 hours before testing. Tell your doctor if you have an infection, as this can also interfere with the results. As well, let him know if you take blood thinners or aspirin.
The PSA test
The PSA test itself is a simple blood test. Your doctor or a hospital technician will draw a sample of blood and send it to the laboratory for analysis. You or the doctor will press a square of gauze to the site to stop any bleeding and prevent bruising. You will not require a recovery time, and you may return to your normal activities immediately afterward.
Interpreting the results
As mentioned earlier, it’s important to keep in mind that a PSA test is not conclusive. PSA levels of 0.0 to 4.0 ng/mL are generally considered to be normal. According to WebMD, men with a PSA between 4.0 to 10.0 ng/mL have a 15% chance of having prostate cancer, while the risk increases to 67% in men with a PSA over 10 ng/mL. However, it is possible to have a low PSA and have prostate cancer, just as it is possible to have a high PSA and not have prostate cancer. Talk to your doctor about what the results might mean, and whether you should have a prostate biopsy.
Read more in our Prostate Cancer Health Center.