The traditional PSA test is becoming less definitive and more nuanced in diagnosing prostate cancer. In order to avoid complications from side effects, researchers caution against aggressive intervention of a cancer that won't prove lethal. Often, watchful waiting is in order.

There is no universally accepted “normal” PSA level. In the past, a PSA of 4 nanograms per milliliter of blood (ng/ml) or less was considered normal; however, more recent studies have shown that some men with PSAs below 4 have prostate cancer and some men with PSAs over 4 do not have cancer.

Furthermore, a variety of factors can affect the PSA level. In addition to prostate cancer, BPH, and prostatitis, normal PSA levels can be influenced by a urinary tract infection, a prostate biopsy or surgery, bladder tests, and recent ejaculation. Some medications including nonsteroidal anti-inflammatory drugs (NSAIDs), thiazide diuretics, statins, as well as some medications used to treat BPH may lower your PSA level.

Normal PSA Level Results: Reliable?

Most experts agree that the higher the PSA level, the more likely it is that a man has prostate cancer. However, the PSA test is not fool-proof. In fact, some evidence has shown that only 25 percent of men who underwent a prostate biopsy because of a higher PSA actually had prostate cancer.

Studies have also demonstrated that as many as 17 to 50 percent of men with elevated PSAs have a prostate cancer that’s slow-growing and that does not cause symptoms during their lifetime. As a result, there is some concern that these men are being over-diagnosed and subjected to unnecessary risks and consequences of their diagnosis.

These consequences may include erectile dysfunction symptoms, infection, or bleeding. The psychological toll of knowing you have cancer may cause significant anxiety and stress. If these men opt to undergo biopsy and/or treatment, they may be exposing themselves unnecessarily to possible side effects (infection, urinary incontinence, erectile dysfunction, etc.).

Are There Official Recommendations About PSA Testing?

There is conflicting opinion about PSA testing for prostate screening among different organizations. This is in part due to conflicting data from a number of large studies on PSA testing.

The National Cancer Institute conducted a Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial, comparing men who underwent annual PSA and DRE screenings with men who were not screened. Findings showed that early identification of prostate cancer did not result in lower death rates—and may have led to over-treatment.

On the other hand, a large European trial found men screened with PSA had both a higher incidence and a lower death rate than men who were not screened. In 2012, the United States Preventive Services Task Force (USPSTF) concluded that the benefits to PSA screening did not outweigh the potential harms associated with over-diagnosis and over-treatment. A recent study determined that PSA screening has declined 18 percent since these recommendations were issued and that the detection of early-stage prostate cancer has also declined while the detection of late-stage cancer has remained the same, further fueling the debate over PSA screening.

Age-specific screening recommendations differ among various health organizations, including the American Urological Association (AUA) and the American Cancer Society (ACS). Most organizations agree, however, that screening should be individualized based on risk factors, age, and overall health, whether or not you are experiencing prostate cancer symptoms, along with open dialogue between patient and healthcare provider.

Men at higher risk, whether because of family history or race, may want to begin that dialogue with their healthcare providers at an earlier age. Older men, particularly those older than 75 or those with a life expectancy of less than 10 years, may not need to be screened.

Originally published in 2016, this post is regularly updated.