Prostate Screening

The PSA blood test

This page has information about the PSA test – a blood test that can help diagnose prostate problems, including prostate cancer. 

There are advantages and disadvantages to having a PSA test. You’ll need to talk to your GP or practice nurse about these before deciding whether to have one.

What is the PSA blood test?

The PSA test is a blood test that measures the amount of prostate specific antigen (PSA) in your blood. PSA is a protein produced by normal cells in the prostate and also by prostate cancer cells. It’s normal to have a small amount of PSA in your blood, and the amount rises slightly as you get older and your prostate gets bigger. A raised PSA level may suggest you have a problem with your prostate, but not necessarily cancer.

Who can have a PSA blood test?

You have the right to a PSA test if you’re over 50 and you’ve thought carefully about the advantages and disadvantages. If you’re black or you have a family history of prostate cancer, this can increase your own risk – so you may want to speak to your GP about having a PSA test from the age of 45.

You may also be offered a PSA test if you have symptoms of a possible prostate problem.

Some men are offered a PSA test as part of a general check-up. You should still think about the advantages and disadvantages and whether the test is right for you before agreeing to have one.

What could affect my PSA level?

Prostate specific antigen (PSA) is produced by healthy cells in the prostate, so it’s normal to have a small amount of PSA in your blood. The amount rises as you get older because your prostate gets bigger.

Prostate problems, such as an enlarged prostate, prostatitis or prostate cancer, can cause your PSA level to rise – but lots of other things can affect your PSA level too, including the following.

• A urine infection – You may have a test for a urine infection as this can raise your PSA level. If you have an infection, you’ll be given treatment for this. You’ll need to wait until the infection has gone – around six weeks – before you have a PSA test.
• Vigorous exercise – You might be asked not to do any vigorous exercise in the 48 hours before a PSA test.
• Ejaculation – You may be asked to avoid any sexual activity that leads to ejaculation in the 48 hours before a PSA test.
• Anal sex and prostate stimulation – Receiving anal sex, or having your prostate stimulated during sex, might raise your PSA level for a while. It might be worth avoiding this for a week before a PSA test.
• Prostate biopsy – If you’ve had a biopsy in the six weeks before a PSA test, this could raise your PSA level.
• Medicines – Let your GP or practice nurse know if you’re taking any prescription or over-the-counter medicines, as some might affect your PSA level. For example, some medicines used to treat an enlarged prostate, known as 5-alpha-reductase inhibitors such as finasteride (Proscar®) or dutasteride (Avodart®), can reduce your PSA level and give a false test result.
• Other tests or surgery – If you've had any tests or surgery on your bladder or prostate, you may need to wait up to six weeks before having a PSA test.
• Urinary catheters – If you have a catheter to drain urine from your bladder, you may need to wait up to six weeks after it has been put in before having a PSA test

What happens next?

If your GP thinks your PSA level is higher than it should be for your own situation, they may arrange for you to see a specialist at the hospital. For example, they might make an appointment for you to see a specialist if your PSA level is 3 ng/ml or higher. But this is just a guide and slightly higher levels may be normal in older men.

They might refer you to a specialist if your PSA level is lower than 3 ng/ml but you have an increased risk of prostate cancer for other reasons, such as your family history.

If your GP thinks you could have prostate cancer, you will usually see a specialist within two weeks. You may hear this called a 'two-week wait' or 'fast-track' referral.

If your GP thinks something else has caused your PSA level to be raised, they might suggest having another PSA test in the future to see if your PSA level changes, rather than seeing a specialist straight away.

Your GP should discuss all of this with you, to help you decide what to do next.

Find out more via the Prostate Cancer UK Information Leaflet: understanding_the_psa_test-ifm.pdf (prostatecanceruk.org)