The PSA test is a blood test that can detect the early signs of an enlarged prostate. It is the most common initial test for men who are worried about prostate cancer.
The test, which can be done at a GP surgery, measures the level of prostate-specific antigen (PSA) in your blood.
PSA is a protein made only by the prostate gland. Some of it will leak into your blood, and the amount depends on your age and the health of your prostate.
Raised PSA levels
The amount of PSA in your blood is measured in nanograms of PSA per millilitre of blood (ng/ml). PSA levels can range from less than 1ng/ml to hundreds of ng/ml.
- If you're aged 50 to 69, your PSA level is considered raised if it's 3ng/ml or higher.
A raised PSA level in your blood may be a sign of prostate cancer. However, other conditions, such as an enlarged prostate, prostatitis, or a urinary infection, can also cause a raised PSA level.
There are well-known issues with the accuracy of the PSA test and potential harmful consequences, which is why there is currently no national screening programme for prostate cancer in the UK.
Instead, all men over the age of 50 can access quality information about the PSA test and discuss the option of having a free test with their GP as part of a scheme called the prostate cancer risk management programme (PCRMP).
Under PCRMP, your GP will be expected to discuss with you the benefits, limitations, and risks of the PSA test to help you decide whether or not to have it.
You should also be given a leaflet about PSA testing for prostate cancer. The leaflet provides similar, but more detailed, information to what you'll find on this page.
Men are at higher risk of prostate cancer if they have a family history of prostate cancer, are of black ethnic origin, or are overweight or obese.
If you are worried about prostate cancer, you should talk to your GP. Read more about prostate cancer, including the symptoms of prostate cancer and treatments for prostate cancer, in our Health A-Z section.
Pros and cons of the PSA test
Pros
- It may reassure you if the test result is normal.
- It may give you an indication of cancer before symptoms develop.
- It may find cancer at an early stage, when treatment could prevent the cancer becoming more advanced.
- PSA testing may reduce your risk of dying from prostate cancer by 21%.
- If treatment is successful, you may avoid the risks of advanced cancer.
- In cases of advanced cancer, treatment will usually extend life.
Cons
- It can miss cancer and provide false reassurance.
- It may lead to unnecessary worry and medical tests when there is no cancer.
- It cannot tell the difference between slow-growing and fast-growing cancer.
- It may make you worry by finding slow-growing cancer that may never cause any symptoms or shorten your life.
- To save one life from prostate cancer, 27 men would have to be diagnosed with it.
Before having the test
If you're having a PSA test, you should not have:
- an active urinary infection
- ejaculated in the last 48 hours
- exercised heavily in the last 48 hours
- had a prostate biopsy in the last six weeks
Each of these may give an inaccurate PSA reading.
What happens after the test?
There are usually three main options after a PSA test.
A normal PSA level
If your PSA level is not raised, you are unlikely to have cancer. No immediate action is needed, although you may have further PSA tests in the future. However, the PSA test doesn't always pick up prostate cancer.
A slightly raised PSA level
Three out of four men with a raised PSA level will not have prostate cancer. If your PSA level is slightly higher than normal, you probably don't have cancer, but you might need more PSA tests.
A raised PSA level
One in four men with a raised PSA level will have cancer. The higher the level of PSA, the more likely it is to be a sign of cancer. If your PSA level is definitely raised, your GP will arrange for you to see a specialist for further tests to find out if you have prostate cancer.
A PSA test alone cannot tell you whether you have prostate cancer. Your doctor may also perform a digital rectal examination (DRE). This is an examination of the prostate gland, during which the doctor will insert a gloved finger into your rectum.
The DRE checks for signs of prostate cancer, such as the prostate gland feeling hard. However, a gland that feels normal does not necessarily mean you don't have cancer.
Many early cancers may not be detected by a DRE, so a DRE is not recommended as a substitute for the PSA test.
Your doctor will also consider your age, any family history of prostate cancer, your ethnic background, and any previous PSA test results.
In some cases, extra PSA tests may help make the situation clearer or show any changes.
Key PSA facts
- About 15 out of every 100 men who have a normal PSA test result do have prostate cancer.
- About 75 out of every 100 men who have an abnormal PSA test result do not have prostate cancer.
- Biopsies miss one in five prostate cancers.
Biopsies and further testing
If your PSA level is raised, a biopsy, which involves taking tissue samples from the prostate gland, may be needed to check if you have cancer.
Prostate biopsies can miss some cancers. One in five cancers are missed at prostate biopsy. You may not know for sure that you don't have cancer after a clear result, and biopsies sometimes have to be repeated.
Biopsies can sometimes cause complications. The most common is bleeding followed by infection. Most men experience blood in the urine and blood in the sperm after a biopsy. Antibiotics will be given to prevent infections.
Prostate cancer treatment
If early prostate cancer is found, the treatment you receive will depend on your individual circumstances. The type and size of the cancer and your general health are among factors that will be considered when deciding on the right type of treatment.
Most types of treatment, such as surgery and radiotherapy, come with serious side effects, including erection, fertility, and bladder problems.
Read more about treating prostate cancer.
You should talk to your consultant about the benefits and risks of any treatment before you begin.
Article provided by NHS Choices