- What is a PSA test?
- Why is it done?
- What does it involve?
- Who should have the test done?
- How can I prepare for it?
- What does the procedure feel like?
- How accurate is a PSA test?
- What would a bad result mean?
- What are the side effects and complications?
The PSA test is a blood test that measures the amount of prostate-specific antigen (PSA) in the blood. This is a protein produced by normal and abnormal cells in the prostate, but too much PSA may suggest problems with the prostate.
The PSA test is done to diagnose prostate problems, including prostate cancer. Early detection of prostate cancer can be important in getting appropriate treatment in time.
If you have already been diagnosed with prostate cancer, the procedure can be used to test how effective the treatment is and check for any recurring cancer.
The PSA test can be done at your GP surgery. It involves a simple blood test, usually drawn from the arm, that is then sent to a laboratory to be tested.
If you’re over the age of 50, or 45 and over with a family history of prostate cancer or you are in a high-risk group, you should talk to you GP about testing your PSA levels.
How can I prepare for it?
Before having the PSA test, your GP will talk about the advantages and disadvantages of the test and talk about your risk of having prostate problems or cancer. They will also carry out a physical exam of the prostate, look at your medical history, and any previous prostate biopsy results. Sometimes your GP will perform a digital rectal examination and urine test to rule out any urinary infection.
If you don’t have any prostate symptoms or you have another serious health condition, your doctor may recommend not to go ahead with the test.
You may be asked to avoid rigorous exercise and ejaculation for 48 hours before the test, as this can raise PSA levels in the blood. It may be advised to avoid anal sex and any form of prostate stimulation for a week before the test, as this too can raise the levels of PSA in the blood.
The PSA test is just a simple blood test. However, the doctor will physically examine your prostate and may perform a urinary test if they believe an infection might be present. A physical examination involves having your GP gently insert a lubricated finger into the rectum to feel the prostate. It is usually a quick process and should be uncomfortable but not painful.
According to the NHS, three out of four men with raised PSA levels will not have cancer. Additionally, it may miss approximately 15 per cent of prostate cancer. Many men with raised PSA levels don’t have prostate cancer and some men who have prostate cancer have normal PSA levels.
A PSA test alone won’t diagnose prostate cancer. A digital rectal exam, whether or not you’re at high risk of cancer, and any previous test results will all need to be taken into consideration.
Other forms of the test may be done to improve result readings. These may include:
- Change in PSA levels over time (PSA velocity). A rapid rise in levels may signal aggressive cancer.
- Percentage of free PSA (PSA not attached to other cells in the blood). The more PSA that is attached to cells can increase chance of having cacner.
- PSA per volume of tissue (PSA density). A higher density can be caused by cancer. An MRI or transrectal ultrasound are usually used to measure PSA density.
A raised PSA level in the blood can be a sign of a problem with the prostate gland. It could signal:
- an enlarged or inflamed prostate
- prostate cancer
Other factors that can cause PSA levels to rise include:
- a urine infection
- intensive exercise
- ejaculation 48 hours before the test
- anal sex 48 hours before the test
- prostate biopsy: should be avoided for up to 6 weeks before the test
- certain medications
If your PSA levels are high, your doctor may refer you to a specialist urologist; or if there are obvious reasons for high levels of PSA, they may simply suggest that you repeat the test in the future to see if the level changes.
Side effects and complications that may occur from the procedure include:
A false-positive result may lead to other medical procedures being done, which may have their own side effects. If a biopsy is taken, there may be bleeding, infection, and/or pain.