The PSA Test: What to Expect

The prostate-specific antigen (PSA) test is a blood test that measures your PSA levels and is used to screen for prostate cancer. Generally, high PSA values indicate a higher risk of receiving a prostate cancer diagnosis. Men with prostate cancer usually have higher PSA levels.

Beyond prostate cancer screening, the PSA test can also help monitor how patients respond to treatment for prostate cancer. In such cases, high PSA values may highlight further disease progression.

Learn more: Should You Take the PSA Test?

A few factors may affect your PSA results, and could lead to inaccurate interpretations. The following should be avoided up to 48 hours before your PSA test:

• Intensive exercise
• Ejaculation

Additionally, If you have had a urinary tract infection or prostate biopsy recently, you may need to wait to take the test..

You should inform your doctor of all your current medications and supplements, as some may interfere with your results. There are some medications to avoid before the PSA test. While some supplements may help lower your PSA levels, they may not reduce your risk of prostate cancer and instead, simply mask the disease.

The PSA test is a simple blood test, and usually does not require any special preparations. You should wear a top with sleeves that can roll up easily.

During the PSA test, a nurse will draw a small vial of blood. You may feel a slight prick or pinch as they insert the needle.

Afterwards, your doctor will send your blood sample to a lab to determine your PSA levels.

The definition of significantly abnormal PSA levels has evolved over the years. Generally, while recommendations may vary, the commonly suggested level for concern is 4 ng/mL.

However, this threshold level was derived from early studies. Now, researchers have found that PSA tends to increase as you age. A new consensus was reached, concluding that PSA thresholds should increase with age. However, bear in mind that exceeding these levels may not confirm prostate cancer.

The American Urological Association’s new suggested threshold levels are as follows:

Other research has suggested that a PSA level between 4 and 10 ng/mL has about a 25% risk of prostate cancer. If the PSA level is above 10 ng/mL, the risk rises to over 50%.

These reference values can help you understand your prostate cancer test results. However, it’s important to remember that the PSA test alone cannot diagnose prostate cancer. Instead, it acts as a form of early triage that helps your doctor quickly decide if you need further tests.

If your doctor sees that your PSA is higher than normal, you will probably need to take the test again. This will happen before starting further tests. A 25–40% chance exists that unexpectedly high PSA levels will return to normal after a retest.

If you do have an abnormally high PSA levels, there may not be a need to panic just yet. PSA is not a perfect tumor marker. Many other benign prostate conditions can also raise PSA levels. A few of these include:

• Prostate inflammation
• Benign prostate hyperplasia
• Ejaculation
• Urinary retention
• Age
• Race (e.g. Black men in the US tend to have higher PSA levels than White men)

Before recommending a biopsy for diagnosis, your doctor may suggest some less invasive tests. These could include a magnetic resonance imaging (MRI) scan or a second biomarker test. These tests will help you and your doctor understand your risk for prostate cancer better.

If your PSA test results are normal and you are not at high risk for prostate cancer, you may not need more follow-ups.

However, if you are at higher risk for prostate cancer (e.g. age, family history or mutations) you may need regular PSA tests. This is a precautionary measure, and the frequency of PSA tests can be discussed with your doctor.

According to the American Cancer Society:

• If your PSA level is less than 2.5 ng/mL, you may extend your follow-up screenings to once every two years.
• If your PSA level is equal or above 2.5 ng/mL, you should follow up with yearly screening instead.

If you are aged 55–69 years old, the American Urological Association suggests:

• If your PSA level is over 1 ng/mL, to screen every two years.
• If your PSA level is below 1 ng/mL, to screen every four years.

Finally, while the PSA test is not the be-all and end-all to diagnose prostate cancer, it serves as an important first step. It can help provide some quantitative reassurance about your cancer risk and guide you on the next best steps to take.

If your doctor believes your PSA test results suggest a high risk of prostate cancer, they may recommend a prostate biopsy. While invasive, this day procedure will help confirm if you have prostate cancer or not.