The PSA (prostate specific antigen) blood test can help detect or monitor prostate cancer. It is also used to help detect prostate cancer in men who have symptoms, but is not recommended for men who do not have symptoms.
What is being tested?
The prostate is a small gland at the base of the bladder in men. It is part of the male reproductive system, and produces the protein PSA. PSA is released into semen but some also enters the bloodstream.
High levels of PSA can be caused by prostate cancer, but they are usually caused by other conditions.
If you have prostate symptoms, you might be asked to have a PSA test. It might help point your doctor in certain directions, but it doesn’t diagnose prostate cancer. The only way to do that is with a biopsy.
If you have been diagnosed with prostate cancer, the PSA test can help monitor your condition. When the levels go up, this suggests the cancer is growing. When they go down, this suggests it might be shrinking.
Do I need the PSA test?
The PSA test is not recommended if you don’t have any symptoms of possible prostate cancer. If you are at higher risk of developing prostate cancer, or if you have symptoms that may indicate cancer, PSA testing may be of more benefit.
Cancer Council Australia and the Royal Australian College of General Practitioners both recommend against routine screening in men without symptoms. That is because the PSA test is not very accurate for screening men without symptoms. High PSA levels can be due to many things, and cancer is just one of them. And a man with prostate cancer can have a normal PSA level.
As there is a range of risks and potential benefits of PSA testing, talk to your doctor to help make an informed decision.
How to prepare for this test
You may be asked to avoid ejaculation and vigorous physical activity that can affect the prostate (such as bicycle riding) in the 2 days before the test.
Understanding your results
It is important to note that PSA is not a test specifically for prostate cancer. A raised PSA level can indicate the possibility of cancer, but can also be caused by many other conditions. PSA levels also increase in all men with age.
The PSA test can provide false positive (raised PSA levels but no prostate cancer) and sometimes false negative (low or normal PSA levels, but prostate cancer is present) results.
The PSA test also cannot tell the difference between slow-growing prostate cancer (that would not cause harm) and cancer that will cause harm.
For all of these reasons, it is important to talk to your doctor about whether to have a PSA test and also about your results.
About PSA testing
About blood testing
Visit our 'Guide to blood testing' to learn more about blood tests in general with information such as:
- what to consider before having the test
- what happens during a blood test
- results accuracy
- blood tests cost
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Last reviewed: August 2018