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What Can Cause a Falsely Low PSA?


Updated October 04, 2010

Written or reviewed by a board-certified physician. See About.com's Medical Review Board.

Question: What Can Cause a Falsely Low PSA?

A falsely low PSA can occur because of several different reasons. If the PSA is falsely low, your doctor may be more inclined to write off the result as "normal" while potentially missing underlying prostate cancer. It is important to have an accurate PSA result in order to determine the likelihood of serious conditions such as prostate cancer.

Possible Reasons for a Falsely Low PSA

Potential reasons for a falsely low PSA include:

  • use of hormonally active medications (for example, estrogen- or testosterone-blocking drugs, such as those used to treat prostate cancer)
  • use of non-steroidal anti-inflammatory medications (Some evidence suggests that these drugs may lower the PSA level.)
  • use of statins (Some evidence suggests that these cholesterol-lowering drugs may lower the PSA level.)

In order to avoid a falsely low PSA level, all of the above should be avoided (if possible) prior to the PSA test. Talk to your doctor before stopping any medications. Typically, a PSA test can be easily rescheduled if necessary.


Freedland SJ, et al. J Natl Cancer Inst. 2008;100:1487-1488, 1511-1518.

Singer EA, et al "Prostate-specific antigen levels in relation to consumption of nonsteroidal anti-inflammatory drugs and acetaminophen" Cancer 2008; 113: DOI: 10.1002/cncr.23806.

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