How to Understand Prostate-Specific Antigen (PSA) Levels

Benefits, Limitations, and Risks You Should Know About

The prostate specific antigen (PSA) test is a common blood test used to assess a person's risk of prostate cancer. The test does not diagnose cancer, but elevations in PSA levels can be a red flag that further investigations are needed.

In addition to screening purposes, the PSA test is also used in people with prostate cancer to categorize their risk of metastasis (meaning the spread of cancer to distant organs). For those who have been treated, the PSA test can also be used to monitor for signs of recurrence (the return of cancer).

There has been controversy surrounding the usefulness of the PSA test for routine screening purposes. As such, the recommendations vary and are limited to those who are seen to be at increased risk of prostate cancer.

This article explains what PSA tests do, when they are used, and what the test results mean (and don't mean). It also explains why PSA screening remains a subject of debate among some public health authorities.

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What Is PSA?

Prostate-specific antigen (PSA) is a type of enzyme found in semen. It is produced in the prostate gland and secreted through two tiny passages, called ejaculatory ducts, to mix with semen during ejaculation.

PSA liquefies the semen so that sperm cells can swim freely. PSA is also thought to liquefy mucus in the female cervix so that the sperm cells can pass into the uterus.

While the majority of PSA is found in semen, there is also a small amount found in the blood. Because rises in PSA levels in semen are consistent with rises of PSA in the blood, the PSA test is considered a reliable marker for prostate problems.

In males with a healthy prostate gland, PSA levels are typically low. However, whenever there is a problem with the prostate, PSA levels can increase.

A higher-than-normal PSA can mean one of several things:

High PSAs may be suggestive of prostate cancer, but they don't always mean cancer is present. Other things can also cause high PSAs.

Challenges in Prostate Cancer Screening

The PSA test is a blood test used primarily to screen for prostate cancer. It is one of the tests that can be used for screening, alongside a digital rectal exam (DRE). The PSA test aims to identify cases of prostate cancer based on high or increasing PSA levels.

With that said, there is no such thing as a "normal" PSA level for males of any age. Moreover, there is no set cutoff point that can tell for sure if a male does or doesn’t have prostate cancer.

In the past, a "normal" PSA was classified as 4.0 nanograms per milliliter (ng/ml) of blood or lower. Anything over 4.0 ng/ml was considered suspicious for prostate cancer.

But, over time, it became clear that males could get prostate cancer well below 4.0 and even 2.5. On the flip side, people with PSAs between 4.0 and 10 often have no evidence of cancer at all.

Because of this, the approach to PSA testing has evolved. Today, it is used in a more dynamic way to assess an individual's risk for cancer based on their age, medical history, and other key risk factors.

How the PSA Test Is Used Today

Based on the PSA result and the individual's risk factors for prostate cancer, a healthcare provider may either order further evaluation (including additional blood tests, imaging tests, or a prostate biopsy) or take a watch-and-wait approach (repeating  PSA tests and DREs at regular intervals to watch for any changes over time).

While some healthcare providers still use 4.0 or higher as the cutoff point at which to start a cancer investigation, others start much earlier at 3.0 or even 2.5. There is some rationale for earlier intervention.

Relative Risk of Prostate Cancer by PSA

According to the American Cancer Society (ACS):

  • Males with PSAs over 10 have a one in two chance of having prostate cancer.
  • Males with "borderline" PSAs between 4.0 and 10 have a one in four chance of having prostate cancer.
  • Males with PSAs below 4.0 have a one in seven chance of having prostate cancer.

As such, clinical experience is needed to make an informed choice. This includes exploring all other possible causes for PSA increases, including certain medications, BPH, prostatitis, and other urological problems. Even riding a bicycle or having recently ejaculated can lead to short-term spikes in PSA levels.

By taking an individualized approach, a healthcare provider can not only determine when PSA testing is appropriate but also when the risks may, in fact, outweigh the benefits.

Controversies and Considerations

Because PSA tests offer only general insights into a person's risk of prostate cancer, there are potential harms associated with the procedure. Chief among these is the risk of overdiagnosis and overtreatment.

According to the National Cancer Institute, PSA tests can certainly help detect prostate cancer, but it is questionable if they actually reduce prostate cancer deaths. This is because many of these tumors are slow-growing and are diagnosed at an age where they are unlikely ever to be life-threatening.

As such, the cancer diagnosis may end up exposing a person to treatments that may cause more harm than good. This includes exposure to surgery, radiation, and chemotherapy that can lead to chronic nerve pain, loss of bladder control, and erectile dysfunction.

Even if there is no cancer, a high PSA result may cause unwarranted anxiety and lead to a needless biopsy. In fact, research shows that only one in four people who undergo a prostate biopsy due to a high PSA end up having prostate cancer.

PSA Screening Recommendations

Periodic prostate cancer screening is recommended for some males. With that said, the public health recommendations vary due in part to uncertainties as to whether the benefits of screening outweigh the risks of overdiagnosis and overtreatment.

Because of this, three leading public health authorities have issued different recommendations regarding PSA screening based on age.

Authority Age Group PSA Recommendations
American Cancer Society 40 to 44 Males at very high risk (namely, those with a father or brother with prostate cancer at an early age)
45 to 49 Males at high risk
  50 and over Males at average risk
American Urological Association 40 to 54 Males at high risk (or those at average risk based on consultation with a healthcare provider)
  55 to 69 If a healthcare provider suggests
  Over 70 No screening if the life expectancy is less than 10 to 15 years
U.S. Preventive Services Task Force 55 to 69 Males at risk of prostate cancer
Over 70 No screening

To this end, the decision to screen or not to screen is an individual one that you would need to make with your healthcare provider.


The prostate-specific antigen (PSA) test is used mainly to screen for prostate cancer. Generally speaking, higher PSA levels are associated with a higher risk of prostate cancer, but it's not always the case. Prostate cancer can sometimes occur when PSA levels are lower, while people with very high PSAs often have no evidence of cancer at all.

Because of this, healthcare providers will take a holistic approach when assessing whether a high PSA requires immediate intervention or a watch-and-wait approach. They will take into account not only your age and risk factors for prostate cancer but also the benefits and risks of treatment.

A Word From Verywell

Although there is some uncertainty as to the benefits of routine PSA screening in males, it shouldn't suggest that it is something you can "blow off." If you are at risk of prostate cancer because of a family history of the disease, it is in your best interest to speak with your healthcare provider about the appropriateness of testing.

On the other hand, if you have symptoms of prostate cancer, don't wait to get a PSA to see if "anything shows up." Instead, speak with your healthcare provider and describe your symptoms, including when they occurred. In such cases, you would need a more extensive evaluation to assess whether cancer or some other condition is at the heart of your symptoms.

12 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Mark Scholz, MD
Mark Scholz, MD, is a board-certified oncologist and expert on prostate cancer.