Prostate cancer is the most common cancer among men in the United States. Because it is usually a slow-growing cancer, early screening and detection are useful for catching it when it’s easier to manage.
The most common prostate screening techniques are digital rectal exams (DRE), performed by healthcare professionals during routine checkups, and PSA blood tests, which can be done at a doctor’s office, laboratory or at home.
What is a PSA test?
PSA blood tests are simple, widely used screening tools for the early detection of prostate cancer. They measure the level of prostate-specific antigen, a protein made by cancerous and non-cancerous cells of the prostate.
Sometimes, elevated PSA can indicate a non-cancerous condition, like prostate inflammation (prostatitis) or prostate overgrowth (benign prostatic hyperplasia).
There is no normal PSA level, though most healthcare professionals once considered levels of 4 ng/mL or lower as normal.¹ Recent studies have shown that, in some cases, men with a PSA lower than 4 ng/mL can still develop prostate cancer.²
Should I take a PSA test?
While PSA screening can benefit some men, reducing their potential likelihood of death from prostate cancer, for others, screening can lead to over-diagnosis and over-treatment.³
The US Preventive Services Task Force recommends that men aged 55–69 should decide whether to have a PSA test after discussing potential benefits and harms with their healthcare professional and recommends against screening for PSA in men who are 70 or older.⁴
If you’re African-American or have a father or brother who had prostate cancer, your doctor might recommend screening as early as age 40 or 45, as these factors are associated with higher risk.⁵
Many organizations recommend combining the digital rectal exam (DRE) with a PSA test, in part because a DRE can sometimes detect cancers in men who have lower PSA levels.⁶ ⁷ ⁸
Are PSA tests accurate?
PSA tests are simple and easy, but they aren’t perfect. Like most screening tests, they have their limitations.
False positives
Almost three-quarters of men with high PSA levels will not have prostate cancer,⁹ which is ultimately determined by prostate biopsy. This high rate of false positives can lead to anxiety and potentially unnecessary follow-up tests, including prostate biopsies, which carry the risk of infection, bleeding and pain.
However, it can be reassuring to know that if your healthcare professional is concerned about your elevated PSA, the next step is often an MRI of the prostate. This painless and non-invasive procedure can help limit unnecessary biopsies.
False negatives
On the other hand, low PSA or “negative” results can be misleading: around 15% of men with a PSA of 4 ng/mL or less will have prostate cancer.¹⁰
Despite this, your healthcare professional may find the results helpful when combined with other tests and your medical history. Your doctor may also use age-adjusted PSA levels (remember, they naturally rise over the years) to determine if your results are a problem or simply a benign sign that you’re getting older.
How to get the most accurate PSA test results
Preparing for your PSA test will help improve its accuracy. PSA levels can be affected by a variety of factors, including prostate enlargement, inflammation and infection, as well as recent exercise or sexual activity.
Here’s what you can do to ensure your test is as accurate as possible:
- Delay the test until you’ve healed from a recent urinary tract infection, which can elevate PSA levels.
- Avoid ejaculating for at least 48 hours before taking the test.
- Avoid heavy exercise before the test.
- Take the test in the morning.
- Do not have a DRE right before your test, as this can release PSA into the bloodstream.
Does a high PSA level mean you have prostate cancer?
Not necessarily. Remember, high PSA levels aren’t enough to diagnose cancer on their own. Instead, PSA tests screen for the possibility of the disease. Your PSA levels will indicate to your healthcare professional whether more tests are needed.
The future of prostate cancer screening
Science is constantly advancing, and tests are evolving. In the future, we expect to have more refined tests, especially for men with an increased risk of prostate cancer.
So far, research is leading towards tests that may use a combination of genetic information, urine and blood for advanced screening and diagnoses.¹¹ ¹² ¹³
Summary
It isn’t perfect, but the PSA blood test continues to be integral for the early detection of prostate cancer. Your healthcare professional can use the results — along with other tests and your medical history — to assess your risk.
If you’re a man 55 and up (or 40 and older with a family history of prostate cancer or other risk factors), you might consider an at-home PSA blood test. If you take the PSA test, be sure to discuss the results with your healthcare professional.
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