What Are the Causes of a False-Positive for the PSA Test?

There are several causes for a false positive on a PSA test

Prostate cancer can cause your prostate to produce increased levels of a protein, prostate-specific antigen, or PSA. Your level of PSA may be high for many reasons though, and false positives on the test are not uncommon.

Definition

A false positive is a result that shows an elevated PSA level, but no cancer is found. According to the National Cancer Institute, "only 25 to 35 percent of men who have a biopsy due to an elevated PSA level actually have prostate cancer."

BPH

An enlarged prostate, or benign prostate hyperplasia (BPH), can cause a false positive on a PSA.

Ejaculation

If you are over 50, having an ejaculation within 48 hours of a PSA test could increase your PSA level and lead to a false positive test result.

Rectal Exam

Your doctor should draw blood for a PSA before doing a digital rectal exam, because the exam can potentially increase your PSA level.

Other Prostate Problems

If your prostate is inflamed or if you are retaining urine, your PSA level can increase and your test will result in a false positive.

Biopsy

A prostate biopsy can increase your PSA level, and your doctor may recommend a waiting period after a biopsy before further testing.

References

• National Cancer Institute
• Johns Hopkins Prostate Bulletin--Understanding PSA