What is the prostate specific antigen (PSA) blood test?

The prostate specific antigen blood test measures the level of prostate specific antigen (PSA) in your blood. PSA is a protein made by the cells in your prostate gland.

The prostate (sometimes called prostate gland) is part of the male reproductive system. It makes a fluid that is a part of semen. Most of the PSA made is released into semen to make it more liquid. Some PSA travels into your bloodstream.

High levels of PSA can be caused by prostate cancer, but there are also other causes. As you get older, PSA levels in your blood generally rise.

High levels of PSA can be caused by:

• prostatitis (inflammation of the prostate)
• benign prostate hypertrophy
• a urinary tract infection
• prostate cancer

PSA levels may temporarily increase with any recent disturbance to the prostate, such as:

• vigorous exercise
• recent ejaculation
• prostate surgery
• anal sex or a prostate examination

There are 2 types of PSA in your blood — free (unbound) PSA or complexed PSA. The most common PSA test measures total PSA, the sum of free and complexed PSA. Your doctor may request a free PSA blood test to try distinguish between prostate cancer and other prostate conditions.

When is PSA blood test used?

High levels of PSA in your blood may indicate prostate cancer. Your doctor might suggest a PSA test if you have symptoms of a prostate condition. These may include:

• needing to urinate frequently or suddenly
• discomfort or difficulty when urinating
• blood in your urine or semen

Your doctor may also recommend a PSA test if you:

• have a family history of prostate cancer
• have a higher risk of developing prostate cancer
• are aged between 50 and 69 years

Talk to your doctor about the risks and benefits of PSA blood testing and screening. Your doctor will check for symptoms and risk factors. They may also perform a physical examination of your prostate by inserting a gloved finger into your rectum to feel your prostate.

The PSA test is not recommended as a screening test for prostate cancer in males with no symptoms or family history.

If you do not have symptoms of a prostate problem but would like a PSA test, you should discuss this with your doctor. It can be a good screening tool, but you cannot rely on this test alone to diagnose prostate cancer.

It is possible to have prostate cancer with a normal PSA level. It is also possible to have prostate cancer with only slightly raised PSA levels.

PSA levels may be more useful if they are followed over time with multiple tests, rather than as a one-time blood test.

The only definitive way to diagnose prostate cancer is with a biopsy. An MRI scan of the prostate can help work out if a biopsy is needed.

If you have prostate cancer, monitoring your PSA levels can help your doctor monitor your condition. An increase in PSA may suggest that the cancer is growing.

Where can I get a PSA blood test?

You usually need to go to a pathology collection centre with a referral from your doctor. Your doctor will recommend one near you.

Sometimes, your doctor will collect blood for testing in their clinic. Blood tests are also routinely done in hospitals.

How do I prepare for a PSA blood test?

PSA levels can be affected by disturbances to your prostate.

It may be best to avoid ejaculation and vigorous physical activity (such as cycling) in the days before your test. Vigorous activity can cause a temporary (short-term) increase in your PSA blood levels.

If you are having other blood tests done at the same time, you may need to prepare. Check with your doctor or the pathology collection centre if there is anything you need to do before your blood test.

What happens during a PSA blood test?

A health professional will take a sample of blood, usually from a vein in your arm. The blood will then be sent to a laboratory for testing.

What do my PSA blood test results mean?

A high PSA blood test result may be because of prostate cancer, but remember, there are many other possible causes. You may also have prostate cancer with a normal PSA level.

PSA blood levels also increase gradually as you get older.

It is important to talk to your doctor about your results and what they mean for you.

If you have high levels of PSA, your doctor may recommend:

• a digital rectal exam to physically examine your prostate
• other tests to try and find the cause of your raised levels
• repeating the PSA blood test to measure your levels at multiple time points
• a biopsy or MRI to check for prostate cancer

Resources and support

About PSA blood tests

See Pathology Tests Explained for more information about the PSA blood test.

See the Prostate Cancer Foundation of Australia for resources on the PSA blood test.

You can also call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak to, 24 hours, 7 days a week.

About blood testing

Visit healthdirect's 'Guide to blood testing' to learn more about blood tests in general including information such as:

• what to consider before having a blood test
• what happens during a blood test
• the accuracy and meaning of your results
• the costs of your blood tests

Other languages

Find multilingual resources to help you understand your PSA results and risks of prostate cancer, visit the Prostate Cancer Foundation of Australia.

Looking for information for Aboriginal and/or Torres Strait Islander people?

You can read more about prostate cancer and its diagnosis and treatment on the Prostate Cancer Foundation of Australia website.