Understanding Your PSA Results

What the Prostate Test Tells Us and Doesn't Tells Us

Black woman doctor talking to patient in hospital
David Sacks/Getty Images

Many older men will be familiar with the prostate-specific antigen (PSA) test which doctors routinely use to screen for prostate cancer. While many people will refer to it as the "prostate cancer test," it doesn't actually detect cancer but rather an inflammation of the gland itself.

PSA is a specialized protein naturally produced by the prostate gland. If there is any abnormality or infection of the gland, the resulting inflammation will trigger the release of additional antigens. The higher the PSA level, the greater the inflammation.

Prostate cancer is just one of the conditions the PSA test can help diagnose. While a high PSA may be suggestive of a malignancy, the test alone cannot offer a diagnosis. For this, other lab tests and evaluations would be needed.

Non-Cancerous Causes of a High PSA

The PSA test was originally approved by the U.S. Food and Drug Administration in 1986 to monitor the progression of prostate cancer in men diagnosed with the disease. By 1994, it was clear that the test also had value in detecting prostatic inflammation in otherwise symptom-free men.

While prostate cancer is clearly the main focus of concern, other non-cancerous conditions can also cause the PSA to rise. The most common of these is prostatitis (inflammation of the prostate gland). It is, in fact, the most common cause of prostate problems in men under 50 and can take several forms:

  • Acute bacterial prostatitis, most often caused when bacteria leaks from the urinary tract into the prostate gland
  • Chronic bacterial prostatitis, characterized by persistent inflammation
  • Chronic non-specific prostatitis, for which there may be symptoms but no known cause
  • Chronic asymptomatic prostatitis, for which inflammation is present but with no symptoms

Another cause for elevated PSA levels is benign prostatic hyperplasia (BPH), a condition by which the gland itself becomes enlarged. BPH is primarily seen in older men and may cause uncomfortable urinary symptoms, including the impairment of the urinary flow. While it isn't entirely clear what causes BPH, many believe it to be related to changes in sex hormones as men get older.

BPH is neither cancerous nor indicative of cancer. However, it is important to diagnose and treat as it can lead to complications such as urinary tract infections (UTIs), bladder stones, bladder damage, and kidney damage.

Detecting Prostate Cancer

In the past, doctors typically considered PSA levels of 4.0 or below to be normal. If levels were above 4.0, doctors would consider that to be a red flag for cancer and immediately order a biopsy.

In recent years, however, doctors have come to understand that there is no real "normal" PSA value. In fact, men with a low PSA can end up having cancer, while those with PSAs well above 4.0 could be entirely cancer-free.

As such, current guidelines recommend the use of both a PSA and digital rectal exam (DRE) as part of voluntary prostate cancer screening. The DRE is a physical exam in which a finger is inserted into the rectum to evaluate the size and consistency of the gland. It is performed irrespective of PSA values and can be useful in spotting any abnormalities not detected by the PSA test.

The PSA test and DRE are recommended in men over 50 as well as those between the ages of 40 and 49 whose brother or father has had prostate cancer. Based on the results of the tests, the following would typically occur:

  • If the PSA is not elevated and the DRE is normal, the doctor may recommend another screening in a year.
  • If the PSA is elevated but there are no symptoms or abnormalities, the doctor may recommend another PSA test to confirm the results. If it is still high, the doctor would likely want to monitor the condition at regular intervals to watch for any changes.
  • If the PSA is high and there is a suspicious lump, the doctor may recommend additional tests including a urine test (to test for a UTI), X-rays, transrectal ultrasound, or cystoscopy. If prostate cancer is suspected, a biopsy would be recommended.
Was this page helpful?
View Article Sources
  • National Cancer Institute: National Institutes of Health. "Prostate-Specific Antigen (PSA) Test." Bethesda, Maryland; updated October 4, 2017.
  • Pinsky, P.; Prorok, P.; and Kramer, B. "Prostate Cancer Screening — A Perspective on the Current State of the Evidence." N Eng J Med. 2017; 376:1285-89. DOI: 10.1056/NEJMsb1616281.