Prostate Specific Antigen (PSA)
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 mean you have prostate cancer but about two out of three men with a raised PSA level will not have prostate cancer.
Experts disagree on how useful the PSA test is. There is a lot of ongoing research about PSA. At the moment there is no national screening programme for prostate cancer in the UK because it is not certain that the benefits of measuring this blood test outweigh the potential for harms through over-investigation and over-diagnosis.
When you have a PSA test, you should not have:
- An active urine infection.
- Produced semen during sex or masturbation (ejaculated) in the previous 48 hours.
- Exercised heavily in the previous 48 hours.
- Had a prostate biopsy in the previous six weeks.
- Had a digital rectal examination in the previous week.
- Had receptive anal intercourse in the previous 48 hours.
Each of these may produce an unusually high PSA result. Other things that can produce a raised PSA include acute retention of urine, benign prostate enlargement, older age, having a urinary catheter and prostatitis (prostate infection).
If you decide to have a PSA test, your doctor will give you a digital rectal examination to feel the prostate. This is to find out if the prostate is enlarged or feels abnormal in any way.