Understanding PSA

Content provided by the Faculty of the Harvard Medical School

Welcome to this Decision Guide about PSA testing.

Prostate-specific antigen, or PSA, is a blood test used by many doctors to screen for prostate cancer. If you've had your PSA level checked, you may have been told that your results were "normal" or "abnormal." However, some men would like to know more about what their PSA level means.

This tool provides more information about PSA levels, and what's considered to be reassuring or worrisome for men of different ages.

Keep in mind that PSA is simply a screening tool -- used alone, it cannot answer the question of whether or not you have prostate cancer. However, PSA levels are often helpful for deciding which men need further testing or evaluation. High PSA levels can signal prostate cancer, but they can also reflect benign (non-cancerous) growth of the prostate, as well as prostate infections. Only a biopsy can tell whether or not you have prostate cancer or another cause for your increased PSA test.

It's also important to know that many doctors consider PSA testing to be controversial. That's because PSA results can be misleading, but also because there is uncertainty about whether aggressive treatment of prostate cancer makes sense for many older men. While this tool is designed for men who have had their PSA checked, keep in mind that PSA testing may not make sense for everybody. If you have questions about PSA testing, be sure to speak with your health care provider.

In order to understand your PSA results, we'll ask you a series of questions about you and your medical history. Before you begin, it may be helpful to have your most recent PSA result in front of you, as well as results from any prior PSA tests.

We'll start by finding out your age. That's because PSA levels tend to increase with age, and the cut-off for "normal" PSA levels goes up as well.

How old were you when you had your most recent PSA test?

Less than age 50

Age 50 to 69

Age 70 to 75

Over age 75


Medical Reviewer: Faculty of Harvard Medical School Last Annual Review Date: 2006-07-13T00:00:00-06:00