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Prostate Specific Antigen (PSA) Test

Prostate Specific Antigen (PSA) Test

Prostate cancer is a serious condition. The prostate specific antigen (PSA) test is a blood test to see if you might have prostate cancer and to monitor treatment for prostate cancer.

The PSA blood level is also increased in other conditions. So having an increased PSA test result does not mean that you 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.

Cross-section diagram of the prostate and nearby organs

The prostate gland (just called prostate from now on) is only found in men. It lies just beneath the bladder. It is normally about the size of a chestnut.

The tube which passes urine from the bladder (this is called the urethra) runs through the middle of the prostate. The prostate's main function is to produce fluid which protects and enriches sperm.

The prostate often gets bigger (enlarges) gradually after the age of about 50. By the age of 70, about 8 in 10 men have an enlarged prostate. It is common for older men to have urinary symptoms caused by a non-cancerous (benign) enlargement of the prostate. Some men also develop prostate cancer. See separate leaflet called Prostate Gland Enlargement for more details.

Prostate cancer is a cancer which develops from cells in the prostate gland. It is the most common cancer in men in the UK. Each year, about 40,000 men are diagnosed with prostate cancer in the UK. It affects about 1 in 9 men in the UK at some point in their lives. Most cases develop in men over the age of 65.

Prostate cancer is different to most other cancers because small areas of cancer within the prostate are actually very common, especially in older men. These may not grow or cause any problems for many years (if at all). See separate leaflet called Prostate Cancer for more details.

The PSA test is a blood test that measures the level of PSA in your blood. PSA is made by the prostate gland. The PSA level in your bloodstream is measured in nanograms per millilitre (ng/mL).

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 an examination of the back passage with a gloved finger (a digital rectal examination) in the previous week.

Each of these may produce an unusually high PSA result.

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.

The normal range changes as you get older.

PSA Cut-off Values  

Age (years)

PSA Cut-off

40-49 2.0 nanogram/mL or higher
50-59 3.0 nanogram/mL or higher
60-69 4.0 nanogram/mL or higher
70 or older 5.0 nanogram/mL or higher
There are no age-specific reference limits for men older than 80 years of age.

The higher the level of prostate specific antigen (PSA), the more likely it is to be a sign of cancer.

The PSA test can also miss cancer. About 15 in every 100 men who have a normal PSA level do have prostate cancer. A one-off test is not reliable and repeating the test may provide important information.

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.

Other conditions may also cause a raised PSA level, including:

If your PSA level is not raised

You are unlikely to have cancer. No immediate further action is needed but you may need further tests to confirm the result.

If your PSA level is slightly raised

You probably do not have cancer. You might need further tests, including more PSA tests.

If your PSA level is definitely raised

Your GP will refer you to see a doctor who is a specialist for you to have further tests to find out if you have prostate cancer. The specialist will usually arrange for you to have a sample taken (a biopsy) of your prostate gland.

For information about the treatment options for prostate cancer, see separate leaflet called Prostate Cancer.

Further help & information

Prostate Cancer UK

Tel: 0800 074 8383

Prostate Cancer Support Association

Kemp House, 152 City Road, London, EC1V 2NX

Tel: (Helpline) 0800 035 5302, (Admin) 020 7228 5952

Tackle Prostate Cancer

Kemp House, 152 City Road, London, EC1V 2NX

Tel: (Helpline) 0800 035 5302, (Admin) 020 3195 3830

Cancer Research UK

Angel Building, 407 St John Street, London, EC1V 4AD

Tel: (Nurse team) 0808 800 4040, (Switchboard) 020 7242 0200

Macmillan Cancer Support

89 Albert Embankment, London, SE1 7UQ

Tel: (Support Line) 0808 808 00 00

Further reading & references

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but makes no warranty as to its accuracy. Consult a doctor or other healthcare professional for diagnosis and treatment of medical conditions. For details see our conditions.

Original Author:
Dr Colin Tidy
Current Version:
Dr Colin Tidy
Peer Reviewer:
Dr Adrian Bonsall
Document ID:
12689 (v7)
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