The PSA test
The PSA test is a blood test that measures levels of prostate-specific antigen (PSA). Sometimes, raised levels of PSA can be a sign of prostate cancer.
What the test involves
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The PSA test is a blood test. PSA (prostate-specific antigen) is a protein made by the prostate gland, which naturally leaks out into the blood. The PSA test measures the level of PSA in your blood. Sometimes, a raised PSA level can be a sign of prostate cancer. More often, it’s caused by something less serious such as BPH or prostatitis. A single PSA test can’t show whether a prostate cancer is present, or whether it’s slow- or fast-growing.
The level of PSA can also be raised by:
prostate biopsies (taking samples of tissue from the prostate) – PSA should not be tested until three months after a biopsy
having a urinary catheter (a tube to drain urine)
prostate or bladder surgery – PSA should not be tested until three months after surgery
prolonged exercise, such as long-distance running or cycling – this may raise PSA for up to 48 hours
ejaculation – this may raise PSA for up to 48–72 hours.
If you’re taking a drug such as finasteride (Proscar®) to help with urinary symptoms caused by an enlarged prostate gland, this can lower the level of PSA in your blood. This needs to be taken into account if you have a PSA test, so it’s important to let your GP or nurse practitioner know about any medicines you’re taking.
Dr Shiv Bahnot explains the PSA test, what to expect and possible advantages and disadvantages.
How reliable is the PSA test?
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There are still questions about how reliable PSA testing is.
The PSA test is not a test for prostate cancer. It’s a test for abnormalities of the prostate, one of which may be cancer.
Two out of three men with a raised PSA level will not have any cancer cells in their prostate biopsy, while up to one in five men with prostate cancer will have a normal PSA test result.
Screening for prostate cancer
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In the UK, there is currently no screening programme for prostate cancer. This is because we still don’t know how reliable the PSA test is and there isn’t another reliable test.
Research suggests that while the lives of some men could be saved by PSA screening, many more men would be unnecessarily treated for cancers that would never cause serious harm. This is called over-diagnosis or over-treatment.
However, this doesn’t mean that you can’t have a PSA test. The Department of Health has said that any man over 50 who would like the PSA test, even if they don’t have any symptoms, can contact their GP or nurse practitioner who will then discuss the advantages and disadvantages of the test with them.
If you decide to go ahead with the PSA test, your GP can arrange it for you. Alternatively, there are self-test PSA kits available for a small charge from pharmacies or online. However, there are potential problems with these tests and they should be used with caution. Talking to your GP before you decide to use one could be helpful.
You should also make sure you discuss any worrying symptoms or concerns with your GP or nurse practitioner.