Tests and scans
The PSA test is a blood test that measures the amount of prostate specific antigen (PSA) in your blood. It can help to diagnose prostate cancer.
Your doctor or nurse takes a sample of your blood. This can be done at your GP practice. They then send this off to a laboratory to check the amount of PSA.
Go to our information about prostate cancer
You might have a PSA test if you:
have symptoms that could be caused by prostate cancer
are aged 50 and over and have asked your GP for a test
Doctors also check your PSA level as you go through prostate cancer treatment. It can help them see how well treatment is working.
Prostate specific antigen (PSA) is a protein produced by both normal and cancerous prostate cells. It's normal for all men to have some PSA in their blood.
A high level of PSA can be a sign of cancer. It can also be high for other reasons, for example if you have:
ejaculated within the last 48 hours
done vigorous exercise within the last 48 hours
had a urine infection in the last 6 weeks
had a prostate biopsy in the last 6 weeks
had an examination of your prostate (digital rectal examination) before the PSA blood test
There are different guidelines about how long you should wait between these activities and having a PSA test. Ask your doctor what they recommend.
PSA levels also naturally get higher as you get older. A diagnosis of prostate cancer is not made on a PSA level alone.
Find out about the tests you might have to diagnose prostate cancer
Your doctor should explain the risks and possible benefits of having a PSA test.
The PSA level isn't a reliable sign of whether a man has prostate cancer. Some men have prostate cancer but have a PSA level that is normal for their age. Other men have a higher PSA level but don't have prostate cancer.
Your doctor should discuss the test with you and give you enough time to talk about it with your partner or family.
Read more about the risks and possible benefits of the PSA test
PSA is usually measured in nanograms per millilitre of blood (ng/ml). There is no single PSA reading that is considered normal. The reading varies from man to man and the level increases as you get older. Typically, most men have a PSA level of less than 3ng/ml.
Your doctor may refer you to a specialist if your PSA level is over what is considered normal for your age. It’s important to remember that a PSA level higher than 3ng/ml may be normal in older men. Talk to your doctor about your PSA level and what this means for you.
Doctors usually follow guidelines that advise when to refer someone with symptoms to a specialist. These guidelines vary slightly between the different UK nations. It's important to know that your doctor also uses their own experience and judgment when deciding who needs to see a specialist.
Your doctor may refer you to a specialist if your PSA level is:
Age | PSA level |
|---|---|
Between 40 and 49 | more than 2.5ng/ml |
Between 50 and 59 | more than 3.5ng/ml |
Between 60 and 69 | more than 4.5ng/ml |
Between 70 and 79 | more than 6.5ng/ml |
If you are referred to a specialist, they may do a physical examination and check for any other symptoms you might have. You may have other tests such as an and a .
If you are younger than 40 or older than 80
Your GP may follow more specific guidance and use their clinical judgement to decide what to do next.
Prostate glands vary in size and normal ( ) prostate cells also make PSA. This means men with larger prostates are more likely to have a higher PSA, even if they don’t have cancer.
Your doctor may look at something called PSA density. This looks at the size of your prostate as well as your PSA level. They work out the size of your prostate using a scan.
Your doctor then works out your PSA density using a formula:
PSA density = PSA level ÷ prostate size
PSA density helps your doctor decide if you need further tests for prostate cancer.
If you have been diagnosed with prostate cancer, it can also help doctors make decisions about your care. For example, how often you need check ups if you are having active surveillance for early cancer.
There is no national screening programme for prostate cancer in the UK. This is because previous research showed that the PSA test isn’t a reliable test that can pick up prostate cancer that needs treatment. This means that the PSA test can:
miss some cancers - this is called a false negative
suggest someone has cancer when they don’t - this is called a false positive, and can also lead to overdiagnosis
Research is going on to find a new test. Or to see if the current test is more effective if used in a different way.
If you’re over 50 and want to have a PSA test, you can ask your GP. There are possible risks to having this test that your doctor can discuss with you. They will help you make a decision about whether to have the test.
Find out more about screening for prostate cancer
Go to see your GP if you are worried about symptoms of prostate cancer
Remember that urinary symptoms such as difficulty passing urine are rarely caused by prostate cancer. They are much more likely to be symptoms of non cancerous condition. This condition is called . But it is important to get symptoms checked. Your GP might suggest you have a PSA test.
Last reviewed: 14 May 2025
Next review due: 14 May 2028
Prostate cancer is cancer of the prostate gland. The prostate gland is part of the male reproductive system, and is at the base of the bladder.
Prostate cancer doesn't usually cause any symptoms in the early stages.
You have a number of tests to check for prostate cancer. These may include a digital rectal examination, a PSA blood test, scans and a biopsy.
A blood test is a test to check your general health, the number of blood cells you have and to help diagnose cancer and other conditions.
Find out about tests to diagnose cancer and monitor it during and after treatment, including what each test can show, how you have it and how to prepare.
Prostate cancer is cancer that starts in the prostate gland. The prostate gland is found at the base of the bladder and is about the size of a walnut.
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