PSA Testing Explained

What a PSA number actually means, why a high result is usually not cancer, and how to think about screening.

What PSA measures

PSA — prostate-specific antigen — is a protein made by the prostate and measured with a simple blood test. It is specific to the prostate, but it is not specific to prostate cancer. Anything that irritates or enlarges the prostate can raise it.

Common non-cancerous causes of an elevated PSA include benign enlargement, prostatitis or urinary infection, recent ejaculation, vigorous cycling, a recent catheter or cystoscopy, and simply having a large prostate.

Interpreting a result

There is no single number that separates normal from abnormal. Interpretation depends on your age, prostate size, family history, race, whether you take medications that lower PSA, and — importantly — how the number is changing over time. A stable 5 is a different situation from a 5 that was 2 last year.

An elevated PSA is a reason for further evaluation, not a diagnosis. Most men with a mildly elevated PSA do not have prostate cancer. Often the right next step is simply to repeat the test after treating any infection and avoiding activities that transiently raise it.

What comes after an elevated PSA

If a repeat PSA remains elevated, several tools help decide whether a biopsy is warranted, so that fewer men undergo biopsies they did not need.

Free PSA percentage and secondary blood or urine markers refine risk. Prostate MRI has become central: it identifies suspicious areas, allows targeted rather than random sampling, and a reassuring MRI can sometimes justify continued monitoring instead of biopsy. If biopsy is needed, MRI-fusion targeting improves accuracy.

Should you be screened at all

This is a genuine decision, not an automatic one, and reasonable guidelines differ. The core tension is real: screening reduces prostate cancer deaths, but it also detects slow-growing cancers that would never have caused harm, and diagnosis can lead to treatment with its own side effects.

Broadly, discussion of screening is generally recommended beginning around age 50 for men at average risk, and earlier — around 40 to 45 — for men at higher risk, which includes Black men and those with a father or brother diagnosed with prostate cancer. Screening is generally not recommended when life expectancy is under roughly 10 years, because the benefit takes years to materialize.

The right approach depends on your values and how you weigh those trade-offs. That conversation is worth having properly.