The prostate specific antigen (PSA) test is a blood test. It can help find prostate cancer. PSA is a substance found in semen. It’s made by the prostate. It is normal for some PSA to leak from the prostate into the bloodstream. But sometimes, more than a normal amount of PSA gets into the blood. The PSA test measures the amount of PSA in the blood. If the test shows high blood level of PSA, other tests are needed to help find the cause.
Possible causes of increased PSA
Several things can cause extra PSA to enter the blood, such as:
Enlarged prostate not due to cancer (benign prostatic hyperplasia or BPH)
Prostate infection (prostatitis)
Why a PSA test is done
A PSA test can be done to check for prostate cancer. But the PSA test by itself can’t tell for sure whether or not a man has prostate cancer. And not all healthcare providers agree if men should have PSA tests to screen for prostate cancer. The American Cancer Society and many other organizations advise men talk with their healthcare provider about if prostate cancer screening is right for them. Talk with your healthcare provider about the PSA test beginning around age 50, or earlier if you’re at higher risk.
A PSA test may also be done if a problem is found during a routine prostate exam. And it may be done if you have symptoms that suggest that you have a prostate problem. You may need a PSA if you have symptoms such as:
Having pain when urinating
Having to strain when urinating
Needing to urinate more often
Seeing blood in your urine
Waking often to urinate at night
How a PSA test is done
Right before or after a PSA test, you may have a digital rectal exam (DRE) of the prostate. For this exam, the healthcare provider inserts a lubricated, gloved finger into the rectum to feel the prostate. You’ll also have your blood drawn for the PSA test. The test may be done in the healthcare provider’s office. Or it may be at a lab, clinic, or hospital. Blood is taken from your arm and sent to a lab to be tested.
Getting your results
The time it takes to get your test results varies. Ask your healthcare provider when you can expect your results. You and your healthcare provider will discuss the results together. A normal range for your PSA depends on a number of factors. These include your age and the size of your prostate. They also include your risk factors for cancer, your symptoms, and the results of any previous PSA tests you’ve had. All of these things are taken into account when your PSA tests numbers are checked.
If you're at higher risk for prostate cancer
If you are African American or have a family history of prostate cancer, talk with your healthcare provider about PSA tests by age 40 to 45.
May 19, 2017
Patient education: Prostate cancer screening (Beyond the Basics). UpToDate.
Alteri, Rick, MD,Gersten, Todd, MD