A PSA test is a simple blood test that measures the level of prostate-specific antigen, a protein produced by the prostate gland, in your bloodstream. It’s primarily used to screen for prostate cancer, though elevated levels can also signal non-cancerous conditions. The test is quick, requiring only a standard blood draw, but interpreting the results is more nuanced than a single number might suggest.
What PSA Actually Is
PSA is a protein made by your prostate, a small gland in the male reproductive system that sits just below the bladder and produces the fluid portion of semen. In normal conditions, small amounts of PSA leak into the bloodstream. When something is wrong with the prostate, whether that’s cancer, infection, or simple enlargement, more PSA escapes into the blood. The test measures that concentration in nanograms per milliliter (ng/mL).
What Counts as a Normal Level
PSA levels naturally rise with age as the prostate grows. As a general guideline from MD Anderson Cancer Center, men aged 59 or younger should have a PSA at or below 2.5 ng/mL, while men 60 and older should be at or below 4.0 ng/mL. These aren’t hard cutoffs. Some men with cancer have PSA levels well within the “normal” range, and some men with high PSA have no cancer at all.
Doctors sometimes look beyond a single number. PSA velocity tracks how quickly your levels change over time; a rapid rise can suggest cancer or an aggressive form of it, though recent studies have questioned how reliable this measure is on its own. PSA density adjusts your PSA level for the size of your prostate, since cancers tend to produce more PSA per volume of tissue than benign conditions do. Measuring density typically requires an MRI or ultrasound to estimate prostate size.
Why PSA Rises Without Cancer
A high PSA result does not mean you have cancer. Several common, non-cancerous conditions push PSA levels up. An enlarged prostate (benign prostatic hyperplasia, or BPH), which affects most men as they age, is one of the most frequent causes. Prostatitis, an inflammation or infection of the prostate, is another. Research from Johns Hopkins has shown that the greater the amount of inflammation in prostate tissue, the higher the PSA level tends to be. Scientists believe inflammation disrupts the cells that produce PSA and makes blood vessels in the prostate more permeable, allowing more of the protein to leak into the bloodstream.
Testosterone levels also play a role. Men with higher testosterone tend to have higher PSA levels and greater odds of a clinically elevated reading. This means hormonal fluctuations, medications, or supplements that affect testosterone can influence your results independent of any prostate disease.
How to Prepare for the Test
A few everyday activities can temporarily spike your PSA and lead to a misleadingly high result. To get the most accurate reading, avoid sexual activity, including masturbation, for 48 hours before the blood draw. Ejaculation causes a temporary PSA rise. You should also skip vigorous exercise, especially cycling, for the same 48-hour window. Beyond that, there’s no special fasting or preparation required.
Who Should Get Tested
PSA screening is not a blanket recommendation for all men. The U.S. Preventive Services Task Force considers it a personal decision for men aged 55 to 69. The task force recommends that men in this age group discuss the potential benefits and harms with their doctor and make a choice based on their own values and risk factors. For men 70 and older, the task force recommends against routine PSA screening.
The reason for this cautious approach is overdiagnosis. PSA testing detects many cancers that would never cause symptoms or shorten a man’s life. Analysis of U.S. cancer registry data found that roughly 29% of PSA-detected prostate cancers in white men and up to 44% in Black men represented overdiagnosis, meaning those cancers would not have been found or caused harm without screening. Overdiagnosis leads to overtreatment, which can include surgery, radiation, or other interventions that carry real side effects, including urinary incontinence and sexual dysfunction, for a cancer that may never have progressed.
That said, PSA testing also saves lives by catching aggressive cancers early. The tradeoff is real, which is why the decision is treated as a conversation rather than a routine order. Men with a family history of prostate cancer or Black men, who face higher rates of aggressive disease, may have stronger reasons to begin screening earlier.
What Happens After a High Result
If your PSA comes back elevated, the first step is usually to repeat the test in a few weeks. PSA can fluctuate for many reasons, and a single high reading isn’t enough to act on. If the level stays elevated on the second draw, your doctor will typically move to further evaluation.
That evaluation often starts with newer biomarker tests that use blood or urine samples to detect signals specifically associated with prostate cancer cells. These tests help determine whether a biopsy is likely to find cancer, sparing many men from an unnecessary procedure. If the biomarker results are concerning, the next step is usually a prostate MRI. The MRI can identify suspicious areas within the prostate and, if a biopsy is needed, guide the needle directly to those spots for a more targeted and accurate sample.
A biopsy remains the only way to definitively diagnose prostate cancer. But the pathway from an elevated PSA to a biopsy now includes several intermediate steps designed to filter out false alarms, which means fewer men undergo biopsies they don’t need compared to a decade ago.