Prostate-Specific Antigen

The prostate-specific antigen (PSA) is a blood test. It is used to help detect early forms of prostate cancer. The test is usually used along with other tests. The test is also used to follow the course of those who already have prostate cancer or who have been treated for prostate cancer.

Some factors interfere with the results of the PSA. The factors listed below will either increase or decrease the PSA levels. They are:

  • Prescriptions used for male baldness.

  • Some herbs.

  • Active prostate infection.

  • Prior instrumentation or urinary catheterization.

  • Ejaculation up to 2 days prior to testing.

  • A noncancerous enlargement of the prostate.

  • Inflammation of the prostate.

  • Active urinary tract infection.

If your test results are elevated, your caregiver will discuss the results with you. Your caregiver will also let you know if more evaluation is needed.


No preparation or fasting is necessary.


Less than 4 ng/mL or Less than 4mcg/L (SI units)

Ranges for normal findings may vary among different laboratories and hospitals. You should always check with your caregiver after having lab work or other tests done to discuss the meaning of your test results and whether your values are considered within normal limits.


A normal value means prostate cancer is less likely. The chance of having prostate cancer increases if the value is between 4 ng/mL and 10 ng/mL. However, further testing will be needed. Values above 10 ng/mL indicate that there is a much higher chance of having prostate cancer (if the above situations that raise PSA are not present).

Your caregiver will go over your test results with you and discuss the importance of this test. If this value is elevated, your caregiver may recommend further testing or evaluation.


It is your responsibility to obtain your test results. Ask the lab or department performing the test when and how you will get your results.