What the PSA test measures and why doctors order it

The prostate-specific antigen (PSA) test measures a protein your prostate gland produces. A blood sample is drawn, usually at your doctor's office or a lab, and sent to a laboratory to measure how much PSA is in your bloodstream. Higher levels can signal prostate cancer, but they can also mean a benign enlarged prostate, a urinary tract infection, or recent ejaculation — which is why the test alone cannot diagnose cancer.

Doctors typically order a PSA test as part of prostate cancer screening, usually starting at age 50 for men at average risk. Men with a family history of prostate cancer or Black men, who have higher prostate cancer rates, may be offered screening earlier — sometimes at 40 or 45. The test is also ordered when a man reports urinary symptoms or when a digital rectal exam (DRE) feels abnormal.

The PSA test is not a diagnosis. A high result means your doctor will likely recommend further testing, such as a repeat PSA test, an ultrasound, or a biopsy, to determine whether cancer is actually present.

Key Takeaways

  • The PSA test measures a protein in your blood; higher levels can signal prostate cancer but also benign conditions like enlarged prostate or infection.
  • Screening typically begins at age 50 for average-risk men, but men with family history or Black men may be offered screening at 40 or 45.
  • A high PSA result does not mean you have cancer — your doctor will order follow-up tests to confirm whether cancer is present.
  • The test has both benefits (catching cancer early) and risks (false positives leading to unnecessary biopsies and anxiety), which you should discuss with your doctor before screening.
  • Medicare covers PSA screening once per year for men age 50 and older; coverage varies by insurance plan.

What PSA levels mean and when follow-up testing happens

PSA is measured in nanograms per milliliter (ng/mL). A PSA level below 4 ng/mL is generally considered normal, though some doctors use slightly different cutoffs. A result of 4 to 10 ng/mL is considered borderline and usually triggers a conversation with your doctor about whether to repeat the test, monitor over time, or move to further testing. A PSA above 10 ng/mL typically leads to additional testing.

However, PSA levels vary by age and can change over time. A man in his 70s may have a naturally higher PSA than a man in his 50s. Your doctor will look at your individual result, your age, your family history, and how your PSA has changed over previous tests — not just the single number. Some men with PSA levels above 4 never develop cancer; others with lower levels do.

If your PSA is elevated, your doctor may recommend a repeat test a few weeks later to see if the result was a one-time spike. If it remains high, further testing usually includes a transrectal ultrasound (TRUS) and a prostate biopsy, in which a needle removes small tissue samples from the prostate so a pathologist can look for cancer cells under a microscope.

Benefits and risks of PSA screening you should understand

The main benefit of PSA screening is that it can detect prostate cancer early, when treatment is often more effective and less invasive. Catching cancer before it spreads outside the prostate gland gives you more treatment options and generally better outcomes.

The risks are real and worth discussing with your doctor before you decide to be screened. A false positive — a high PSA that does not indicate cancer — can lead to a biopsy, which carries a small risk of infection, bleeding, and pain. Many men experience anxiety while waiting for biopsy results. Additionally, some prostate cancers grow so slowly that they never cause harm in a man's lifetime, yet screening and treatment can cause side effects like erectile dysfunction and urinary incontinence. This is called overdiagnosis — finding and treating a cancer that would never have caused problems.

Major medical organizations, including the American Cancer Society and the American Urological Association, recommend that men have a conversation with their doctor about the benefits and risks before deciding whether to be screened. This conversation should happen before age 50 (or earlier if you are at higher risk) so you can make an informed choice.

How to prepare for a PSA test

The PSA test itself requires minimal preparation. You do not need to fast or avoid food beforehand. However, timing matters: avoid the test for 48 hours after ejaculation, because ejaculation can temporarily raise PSA levels and produce a false high result. If you have had a recent urinary tract infection or prostate biopsy, tell your doctor, because these can also elevate PSA temporarily.

The test takes only a few minutes. A nurse or lab technician draws a small blood sample from your arm, usually from the inside of your elbow. The sample is labeled and sent to a laboratory, where it is analyzed. You will receive results within a few days to a week, usually by phone or through your doctor's patient portal.

Before your test, write down any questions you have about what the results mean and what happens if your PSA is high. Bring a list of any medications or supplements you take, in case your doctor needs to know about them.

Medicare and insurance coverage for PSA screening

Medicare Part B covers one PSA test per year for men age 50 and older at no cost to you (you pay no copay or coinsurance). The test must be ordered by your doctor as part of a screening visit. If your doctor orders multiple PSA tests in one year, Medicare will cover only one.

If you have a high PSA result and your doctor orders a repeat test within the same year, Medicare may cover that second test if it is medically necessary — but you should check with your doctor's office beforehand, because coverage rules can vary by situation.

Private insurance plans vary widely. Some cover PSA screening annually with no cost to you; others require a copay or coinsurance. Some plans may not cover screening for men under 50 unless there are symptoms or risk factors. Contact your insurance company or check your plan documents to learn what your coverage includes. If you do not have insurance, community health centers and some hospitals offer low-cost or sliding-scale screening.

What to do if your PSA result is high

A high PSA result does not mean you have cancer. Your first step is to schedule a follow-up appointment with your doctor to discuss the result in context — your age, your previous PSA history, your symptoms (if any), and your risk factors. Your doctor may recommend a repeat PSA test in a few weeks to see if the result was temporary.

If your doctor recommends a biopsy, ask questions: Why does he or she think a biopsy is necessary? What will the biopsy tell you? What are the risks and recovery time? How many samples will be taken? Will you be awake or sedated? Some men choose to get a second opinion from another urologist before proceeding with a biopsy, and that is a reasonable choice.

If a biopsy shows cancer, your doctor will discuss treatment options with you, which may include active surveillance (monitoring without when ready treatment), radiation, surgery, hormone therapy, or chemotherapy, depending on how aggressive the cancer is and your age and overall health. You will have time to think about your options and seek a second opinion.

Questions to ask your doctor before PSA screening

Before you decide whether to be screened, ask your doctor these questions: Do I have risk factors that make screening more important for me? What are the benefits and risks of screening in my situation? How often should I be tested? What PSA level would prompt follow-up testing? What happens if my PSA is high? How will we decide together whether to do a biopsy?

Your doctor should be willing to spend time on these conversations. If you feel rushed or unheard, it is reasonable to ask for more time or to seek a second opinion from another doctor.

Frequently Asked Questions

Does a high PSA always mean I have prostate cancer?

No. A high PSA can result from an enlarged prostate, a urinary tract infection, recent ejaculation, or a biopsy or cystoscopy done recently. Only a biopsy can confirm whether cancer is present. Many men with elevated PSA do not have cancer.

How often should I have a PSA test?

That depends on your age, risk factors, and previous results. Most doctors recommend annual screening for men age 50 and older at average risk. Men with a family history or Black men may start at 40 or 45. If your PSA is very low and stable, your doctor may recommend testing every two years. Discuss the right schedule for you with your doctor.

What is the difference between a PSA test and a digital rectal exam?

The PSA test is a blood test that measures a protein. A digital rectal exam (DRE) is a physical exam in which your doctor inserts a gloved finger into your rectum to feel the prostate gland for lumps or hardness. Some doctors recommend both; others use PSA alone. Ask your doctor which screening approach is right for you.

If I have a PSA test, am I committed to treatment if cancer is found?

No. A PSA test and even a biopsy do not obligate you to any treatment. If cancer is found, you have time to discuss options with your doctor, get a second opinion, and decide what is right for you — including active surveillance, which means monitoring without when ready treatment.

Can I refuse a PSA test if my doctor recommends it?

Yes. Screening is your choice. You can decline a PSA test, ask to wait until a later age, or decide to be screened less frequently. Your doctor should respect your decision and discuss your reasons for declining.