Prostate-specific antigen (PSA) is a protein made by the prostate gland. A PSA test is a blood test that checks the level of PSA in a man’s blood. High levels can indicate a number of prostate issues, including inflammation, an enlarged prostate (benign prostatic hyperplasia, or BPH), or prostate cancer.
An estimated 37 percent of men ages 50 and older have had a PSA test in the past year. This screening test offers a way to detect prostate cancer early — up to seven years before symptoms appear.
But certain things, such as medications or an infection, could cause the number on this test to be falsely high or low. Here are nine dos and don’ts before a PSA blood test to ensure that your results are as accurate as possible.
1. Don’t: Fast Before the Test
Some blood tests, like the blood sugar test used to diagnose diabetes, require you to fast for eight hours or more to ensure the correct results. Not this one. “There’s no preparation for a PSA test,” says John L. Phillips, MD, chair and professor of urology at New York Medical College in Valhalla, New York. Not eating beforehand won’t have any effect on the results.
2. Do: Tell Your Doctor Which Medications You Take
A group of medicines called 5-alpha reductase inhibitors can affect PSA levels. These include finasteride (Propecia, Proscar) and dutasteride (Avodart), which doctors prescribe to treat benign prostatic hyperplasia (BPH) and male-pattern baldness.
“They’re designed to block the conversion of active testosterone in the prostate. What will happen is that it will atrophy [shrink] the prostate and artificially lower the PSA,” explains Gabriel Rodríguez, MD, a board-certified urologist at Houston Methodist Clear Lake Hospital. Finasteride can lower PSA results by as much as 50 percent.
A low PSA level could create a false sense of security, he says. You might think your numbers look good, or that they’re going down, when in fact they would have been high. Discuss all the medications you take with your urologist before the test. Ask if you need to come off them, and if so, for how long.
The hair-loss drug minoxidil (Rogaine) is a similar medication that treats baldness, but it’s prescribed at a lower dose and it shouldn’t affect your PSA score.
On the other end of the spectrum are medicines that increase testosterone levels. “Sometimes men will take over-the-counter libido drugs or testosterone supplements. And if they’re ‘juicing up’ in the gym or they’re taking testosterone without supervision, it’s thought to increase the PSA by increasing prostatic stimulation,” says Dr. Phillips.
3. Don’t: Go Cycling Before the Test
Most types of exercise shouldn’t affect PSA levels, with these exceptions: Riding a bike, motorcycle, or Jet Ski puts pressure on the prostate. “It’s going to injure prostatic cells, so they’re going to secrete more PSA into the bloodstream, which will be picked up on the exam,” says Dr. Rodríguez. To avoid a false-positive result, stop doing these types of activities about 48 hours before your test.
4. Do: Get Tested for COVID
If you have symptoms like a fever, cough, sore throat, or loss of taste or smell, get a COVID test. The virus can sometimes elevate the PSA level. One possible reason is that inflammation from a COVID infection damages the prostate, causing some of its cells to shed into the bloodstream. The COVID vaccine may have a similar effect. Ask your doctor how long to wait after a COVID infection or vaccine before getting a PSA test.
5. Do: Take a Break From Sex
During ejaculation, the prostate contracts to propel prostatic and seminal fluid out of the penis. The contraction causes minor trauma to the prostate gland, which then releases small amounts of PSA into the bloodstream, notes Rodríguez.
It’s best to avoid sex or masturbation right before the test, but you don’t have to wait too long. “The PSA usually returns to normal within two days in almost 100 percent of people,” says Phillips. “So avoiding sex longer than two days is probably unnecessary.”
6. Do: Wait Until After Urologic Procedures
Any procedure that places instruments or a scope in or near the prostate might damage this gland. Prostate biopsy and cystoscopy — a test used to diagnose bladder conditions — might temporarily raise PSA levels.Colonoscopy is another possible concern, because the scope passes very close to the prostate on its way up the colon, says Rodríguez.
7. Do: Space Out Your Digital Rectal Exam
The digital rectal exam (DRE) is another test for prostate cancer, in which the doctor inserts a lubricated gloved finger into the rectum to check for any lumps or other changes. Whether a DRE increases PSA has been debated. Some research showed that men’s PSA levels rose after this prostate cancer test. Other studies didn’t find that effect.
If the DRE does raise PSA, it likely won’t be a big rise. “The rectal exam is only four seconds,” says Phillips. “It‘s not going to significantly elevate the PSA.” Just in case, though, your doctor can do the PSA blood draw before the DRE.
8. Do: Wait if You Have a Catheter
Some men need a catheter — a tube placed through the penis into the bladder to drain urine. It’s used for urinary incontinence, urinary retention, and sometimes after prostate or genital surgery. Tell your doctor if you have a catheter. Because this tube can sometimes damage the prostate, you may need to put off the PSA test for up to six weeks after it’s removed.
9. Do: Treat a Urinary Tract Infection
It’s common to have a higher PSA level after a urinary tract infection (UTI) because of the inflammation or irritation that the infection causes. Your doctor can prescribe antibiotics to clear up the infection. Inflammation of the prostate gland, called prostatitis, might also increase PSA levels.
The Takeaway
The PSA test is an important part of screening for prostate cancer. It can detect cancerous changes years before symptoms appear.
Certain things, like infections and medications, may cause false high or low results and make the test less reliable.
Talk to your urologist about how to prepare for your PSA test and follow their directions to help improve the accuracy of your results.
