What is a Prostate Specific Antigen test (PSA)?
Prostate-specific antigen (PSA) is a protein produced by the prostate gland, by both cancerous (malignant) and noncancerous (benign) prostate tissue. A small amount of PSA normally enters the bloodstream. Prostate cancer cells usually make more PSA than benign cells, causing PSA levels in your blood to rise. The PSA level in your bloodstream is measured in nanograms per millilitre (ng/mL).
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.
How can I prepare for the PSA test?
You do not have to prepare yourself for the PSA-test, for example no fasting is needed.
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.
- Had receptive anal intercourse for a period of 48 hours before a PSA test.
How is a PSA test performed?
The PSA test requires a blood sample. Once the test is ordered by the Family Medicine Doctor from the Virtual Clinic you can visit the phlebotomy department in the hospital any time. At the phlebotomy department a blood sample is drawn from a vein in your arm and analysed by our laboratory for PSA, a substance that's naturally produced by your prostate gland.
What are the possible outcomes?
To give an overview of the possible outcomes of the test and the limitations and risks, we listed the categories below. Be aware that the PSA blood level can also be increased in other conditions. So having an increased PSA test result does not mean that you have prostate cancer.
False negative result:
About 15 out of 100 men with a negative PSA test may have prostate cancer.
False positive result:
About 75 out of 100 men with a positive PSA test have a normal prostate biopsy (i.e. no evidence of cancer). Therefore a false positive PSA test may lead to unnecessary investigations, such as a prostate biopsy. There may be side-effects from this investigation, such as bleeding or infection.
A positive result may also lead to unnecessary treatment. Many prostate cancers are slow growing and may not become evident during your lifetime.
If prostate cancer screening detects an abnormality, your doctor may recommend further tests to determine whether you have prostate cancer or not.
What happens after a PSA test?
The Family Medicine doctor from the Virtual Clinic will call you regarding the outcome of your PSA test.
If your PSA level is not raised you are unlikely to have cancer. No immediate further action is needed. The Family Medicine doctor from the Virtual Clinic will inform you that you can come back for regular prostate screening in the agreed timeframe, or if any further tests are needed to confirm the result.
If your PSA level is raised you will be offered an appointment to see an urologist as soon as possible.
How often do I need a PSA test?
Looking at the international guidelines and recent studies the frequency for screening is not straightforward. Following the latest update from the National Comprehensive Cancer Network (NCCN) the below interval is advised. Clinical judgement is used to decide on your follow-up.
- Recommendation to repeat testing every 2 to 4 years if PSA is <1 nanograms per millilitre (ng/mL) for male aged 45 to 75 years old
- Recommendation to repeat testing every 1 to 2 years if PSA is 1 to 3 nanograms per millilitre (ng/mL) for male aged 45 to 75 years old