The PSA Test
If you or your GP are concerned that you might have a prostate problem, your GP will ask for a blood sample from you. This blood sample should only be taken after you have had a urine test to check that you do not have a urinary infection.
The PSA test is not a test specifically for cancer, but can show that there is a problem with the prostate. It should be used together with other tests for diagnosing prostate cancer. Your GP should talk to you about the advantages and disadvantages of having the test and answer any questions you may have before you decide whether to have the test or not.
If you would like more information about the PSA test call our confidential Helpline on 0800 074 8383.
If you decide to go ahead, your blood sample will be sent to a laboratory to test for PSA (Prostate Specific Antigen). PSA is a protein that is only produced by the prostate gland. Its job is to keep the fluid that carries sperm (semen) in a liquid form. All men have some PSA in their blood, and the PSA level can be affected by:
Age
PSA rises with age. The accepted normal PSA test result is up to 2.5 ng/ml for men in their forties, and up to 6.5 ng/ml for men in their seventies 1.
Infection
A urine infection can cause the PSA to rise. You will have a simple urine test to rule out infection before having a PSA test.
BPH (Benign Prostatic Hyperplasia)
BPH is a common condition that mainly affects men over the age of 50. It is a non cancerous enlargement of the prostate. The increase in size may cause the prostate gland to produce more PSA.
Prostatitis
Prostatitis is inflammation of the prostate gland. The inflammation allows more PSA to move from the prostate into the blood and causes the PSA level to rise.
Prostate cancer
Prostate cancer may cause the PSA level in the blood to rise. However, some men with early prostate cancer may not have a raised PSA.
Vigorous exercise
It is not clear whether exercise such as cycling affects the PSA level. You may be advised to avoid vigorous exercise in the 48 hours before a PSA test 2.
Ejaculation
Ejaculation in the 48 hours before a PSA test may affect the results, especially in younger men 2.
Digital rectal examination
There is disagreement over whether a DRE will affect the PSA result. If possible, the PSA test should be done before a DRE 3.
Biopsy
If you have had a biopsy in the last six weeks before a PSA test, this can affect the PSA result 2.
It can take between one and two weeks to get the test results. If the PSA result is abnormally high for your age, your doctor will either repeat the test, or arrange for you to have further tests. The PSA result alone cannot tell you whether or not you have prostate cancer. A high PSA level in the blood can commonly be caused by other conditions as described above. The higher the level of PSA, the greater the risk that prostate cancer is the underlying cause. A normal PSA does not completely rule out prostate cancer.
References used in the production of this page.
1 National Institute for Health and Clinical Excellence. Prostate Cancer: Diagnosis and Treatment; Full Guideline. 2008.
2 Watson E et al. The PSA test and prostate cancer: information for primary care. NHS Cancer Screening Programmes, Sheffield; 2002.
3 Price CP et al. Pre- and post-analytical factors that may influence the use of serum prostate specific antigen and its isoforms in a screening programme for prostate cancer. Ann Clin Biochem 2001; 38: 188-216.