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The Prostate-Specific Antigen (PSA) Test

What is a PSA Test?

The PSA test is the leading method of screening for prostate cancer. PSA screening can help catch the disease at an early stage when treatment may be more effective and potentially have fewer side effects. The PSA test may be done along with a digital rectal exam (DRE), in which a physician inserts a gloved finger into the rectum to examine the prostate for irregularities.

What Does PSA Mean?

PSA, or prostate-specific antigen, is a protein produced by the prostate and found mostly in semen, with very small amounts released into the bloodstream. When there’s a problem with the prostate—such as the development and growth of prostate cancer—more PSA is released. Sometimes, a man’s prostate releases slightly high PSA for other reasons. Rising PSA eventually reaches a level where it can be easily detected by a blood test.

For more information on rising PSA, download or order your free copy of the Prostate Cancer Patient Guide.

What is the PSA Test?

During a PSA test, a small amount of blood is drawn from the arm, and the level of PSA, a protein produced by the prostate, is measured. A higher PSA means that there is a greater chance that you have prostate cancer. Historically, a PSA of  3 or 4 was considered as the threshold of “normal” vs “abnormal.” However, we now know that it’s more complicated, and a high PSA does not necessarily mean that a man has prostate cancer. In some (rare) cases, cancer can be present even when PSA levels are lower.

Your doctor will consider several factors when evaluating the results of your PSA test, such as your age (PSA rises with age). If you have had multiple PSA tests, your doctor will look at the trend, and any rate of rise over time (PSA velocity).

Remember that assessment of PSA must also take into account:

  • Prostate size: A man with a larger prostate may have a higher normal PSA level.
  • Prostatitis: Prostatitis is a painful condition, often caused by bacterial infection in which the prostate is inflamed, swollen, and tender. Prostatitis can cause high PSA.
  • Benign prostatic hyperplasia (BPH): BPH is an enlarged prostate. It may make urination or ejaculation difficult, and along with the swelling, may cause higher PSA levels.
  • Urinary tract infection or irritation: An infection of the urinary tract, as well as irritation caused by medical procedures involving the urethra or bladder, may irritate the prostate and cause it to produce more PSA.
  • Prostate stimulation: Sexual activity, a DRE, or even a long bike ride can cause temporarily high PSA.
  • Medications: Some medications, such as finasteride (Proscar or Propecia) or dutasteride (Avodart), can lower your PSA.

What if My PSA is High?

PSA screening is just the first step, alerting you and your doctor that more testing may be needed. If PSA is only slightly elevated, your doctor may recommend repeating the test a couple of weeks later. From there, other types of tests can help with the decision on whether you need a biopsy, including:

  • Digital rectal exam (DRE), if not already done
  • Free PSA test (measures PSA not bound to proteins in blood; <10% Free PSA indicates greater risk of having cancer; 10-20% is borderline)
  • PSA velocity, or the rate of rise over time (faster increase means more risk)
  • PSA density, or the PSA per volume of prostate (higher density means more risk)
  • PSA-based blood markers (e.g., Prostate Health Index, 4K score)
  • Urinary markers (e.g., EPI test score >15, urinary PCA3 or SelectMDx)
  • Magnetic resonance imaging (MRI) of the prostate

Each time you see your doctor for a checkup, have a conversation about prostate health and prostate cancer screening. PCF recommends that you make a shared decision about PSA screening with your doctor, starting at age 45, or age 40 if you have a family history of prostate or other cancers or are Black.

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