Prostate-Specific Antigen (PSA)

What is PSA?

The prostate-specific antigen test measures the amount of PSA in the blood. PSA is a protein produced by the prostate gland and released in semen during ejaculation, with small amounts circulating in the blood. Both cancerous and noncancerous tissues in the prostate produce PSA. The latter can be bound to protein or circulate “freely” (unbound) in the blood. This test measures the total PSA (both bound and unbound) in the blood.

Prostate cancer is a common illness among men and a leading cause of death. Prostate health, screenings, and treatment fall primarily under the purview of your healthcare provider's urology department. Detecting abnormalities of this gland can save men’s lives.

Prostate cancer progresses slowly and without apparent symptoms, which is why it can be so life-threatening. Prostate cancer only starts displaying symptoms, such as increased incidence of urinary tract infection, in its advanced stages. Some believe that erectile dysfunction is an indicator of prostate cancer, but it is not. However, it is important to understand that erectile dysfunction can occur as a side effect of extreme prostate cancer treatments such as the removal of the prostate.

Because there are few symptoms of prostate cancer, prostate cancer diagnosis relies upon active surveillance of prostate health that checks for high PSA levels versus normal PSA levels. With an early diagnosis, one can receive a timely treatment and prevent any spread of malignancies.

Why take a PSA test?

This is an essential test for men who want to stay healthy and get out in front of their risk of prostate cancer. Getting tested regularly can help detect any abnormalities before they become more pronounced and end up inflicting a heavy burden on you and your life. Even men without elevated risk factors like a family history of cancer should be tested regularly. For men who were already diagnosed with prostate cancer, the PSA test will be needed to follow up on whether their cancer is recurring and the make sure that the treatment path chosen was effective. The PSA test is also used to help detect prostatitis and benign prostatic hyperplasia (BPH).

Men who have abnormal PSA levels need to check with their doctor and plan the next step. Those whose tests show abnormal levels of PSA will have to investigate further. You might need a digital rectal exam (DRE) or a biopsy to conclusively identify cancer. A blood PSA test poses no risk and is included in men’s annual wellness checkup.

For use as a prostate cancer screening test, both the American Cancer Society (ACS) and the American Urological Association (AUA) recommend that men consider potential benefits and risks of testing when deciding.

The ACS recommendations include:

• Begin PSA screening at age 50 for average-risk men.
• Begin PSA screening at age 45 for higher risk men. This includes men who are African-American, or who have a first-degree relative (dad, brother, or son) who had prostate cancer before age 65.
• Begin PSA screening at age 40 for men with 2 or more first-degree relatives who had prostate cancer before age 65.
• Repeat screening annually or every 2 years based on the PSA result.

The AUA recommendations include:

• Begin screening at age 55 and continue through age 69 for average-risk men.
• Repeat screening every 2 years, or at different intervals based on PSA result.
• Consider screening men age 40-54 if they are high risk, including African-American men and men with a family history of prostate cancer.
• Consider continuing to screen men age 70 or older when they are in excellent health (defined by the AUA as men expected to live another 10-15 years).

The National Cancer Institute (NCI) found in 2003 that finasteride and dutasteride, drugs commonly used to treat enlarged prostates and hair loss, may impact prostate cancer risk. Other more recent studies have thrown the connection between prostate cancer and finasteride into question. Nonetheless, men who have used finasteride in the past should consult with their doctors to assess the need to increase prostate cancer screenings.

The PSA test is not designed to replace traditional prostate exams, digital rectal exams, or prostate biopsies.

What can cause PSA levels to rise?

PSA velocity is the rate at which PSA levels change over time, and a rapid rise in PSA is alarming. PSA can be elevated due to many reasons including prostatitis, which is inflammation (swelling), or infection of the prostate. PSA levels can also rise due to an enlarged prostate, also called benign prostatic hyperplasia (BPH). Finally, having prostate cancer can lead to high levels of PSA.

Some factors can lead to elevated PSA levels, stressing out the patient in vain. For example, when a man ejaculates two days before the test, his test will show what is called a ‘false positive’. So, make sure you talk to your physician about it.

What your PSA test results mean?

PSA tests measure PSA in nanograms per milliliter of blood. Normal values of PSA are anything below 4 ng/mL. Values between 4-10 ng/mL are considered elevated and need to be investigated further. A PSA test should be well-analyzed before a doctor can make a diagnosis. Variations of a PSA assessment include the following:

Percentage of free PSA – This test is used to indicate the presence of cancer. When PSA levels are high with a low percentage of free PSA, this indicates a high probability that cancer has developed. Your doctor will likely want to perform a prostate biopsy to check for cancer cells.

PSA with age – Your healthcare provider needs to take into account that PSA levels tend to elevate with age, thus older men will commonly demonstrate higher PSA without necessarily indicating prostate cancer.

Where can I get a PSA test near me?

Please use our Lab Locator to find find a convenient testing location.

NOTE: PSA tests are available through Health Testing Centers for men age 40 and older. If you are younger than 40 and interested in PSA testing, contact your primary care doctor or urologist.

References

1. American Cancer Society. American Cancer Society recommendations for prostate cancer early detection. Available at: https://www.cancer.org/cancer/prostate-cancer/early-detection/acs-recommendations.html.
2. American Urological Association. Early Detection of Prostate Cancer (2018): AUA Guideline. Available at: https://www.auanet.org/guidelines/prostate-cancer-early-detection-guideline. Published 2013; Reviewed and Validity Confirmed 2018.
3. National Cancer Institute. Prostate Cancer Prevention and Finasteride: A Conversation with NCI's Dr. Howard Parnes (2019): Available at: https://www.cancer.gov/news-events/cancer-currents-blog/2019/prostate-cancer-prevention-finasteride-parnes.

Reviewed By: Dr. Kurt Kloss, MD
Last Reviewed Date: Mar 12, 2020