PSA (Prostate Specific Antigen) Blood Test, from our experts to you.
Dr Sam Rodgers MBBS, MRCGP

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What is a
PSA (Prostate Specific Antigen) Blood Test?

Prostate-specific antigen (PSA) can be used in screening and treatment for prostate cancer. Our PSA test can help to detect prostate cancer. Finding cancer early on can improve your chances of being successfully treated. However, a PSA test has several shortcomings when used as a screening test. PSA tests can increase your risk of being treated for cancer that may not be aggressive and may not have affected your lifespan. The side effects of prostate cancer treatment can include erectile dysfunction and urinary incontinence, which can impact your quality of life. Therefore, prostate screening in the UK can be controversial, and we encourage you to do as much research as possible to be aware of the risks and benefits of taking a PSA test.


What are false positive
and false negative PSA results?

False positive results - besides being elevated by prostate cancer, PSA levels can be raised due to urinary tract infections or even certain activities such as recent ejaculation and some forms of exercise. This means there is a risk of PSA being elevated when no cancer is present (a false positive). For every 100 men with a high PSA result, approximately 75 will have a false positive, and 25 will have a true positive (i.e. they will have prostate cancer). Currently, the most reliable way of working out whether you have a true positive or a false positive is through a prostate biopsy. As the PSA test has a high false positive rate, many prostate biopsies will prove unnecessary. However, MRI scans before a biopsy mean that unnecessary biopsies are in decline.

False negatives - this is where the PSA result is in the normal range, but the person has underlying prostate cancer. PSA levels can remain normal in the early stages of prostate cancer, providing false reassurance. If we test 100 men with prostate cancer, approximately 15 would have a normal PSA result (a false negative).

In some cases, prostate cancer grows very slowly and may never cause symptoms or shorten lifespan. A significant proportion of the men who receive a true positive result may undergo surgery they did not need.


When should I see a
doctor for prostate health?

Please see your doctor for an examination if you're experiencing any urinary symptoms, including frequent urination, difficulty starting or stopping the flow of urine, or pain during sex. Do not attempt to diagnose yourself with a PSA test.


What's included?

Prostate
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PSA - Total Prostate Specific Antigen (PSA) is a protein which is released into the blood by the prostate gland. Prostate cancer can raise PSA levels but a PSA test in isolation is not to be relied upon to diagnose prostate cancer, as levels can be raised in benign prostate disorders (a false positive). There is also the potential for PSA levels to be normal despite the presence of prostate cancer, this is called a false negative.

How to prepare
for your test

Special instructions

Prepare for your PSA (Prostate Specific Antigen) Blood Test by following these instructions. Avoid heavy exercise for 48 hours beforehand. Please avoid ejaculating for 48 hours prior to this test. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.


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