Prostate-Specific Antigen (PSA)

A protein made by the prostate, measurable in blood.

PSA is a protein the prostate produces as part of its normal function. Small amounts circulate in every man’s blood. Levels tend to rise when the prostate is enlarged, inflamed, or — sometimes — when cancer is present, which is why PSA is the most widely used marker for keeping an eye on prostate health.

What PSA is

Prostate-specific antigen is an enzyme made by prostate tissue — healthy and otherwise. A screening test measures how much has entered the bloodstream. Levels naturally rise somewhat with age as the prostate grows.

Why levels rise

An elevated PSA has several possible explanations: benign prostate enlargement (very common after 50), inflammation or infection of the prostate, recent ejaculation or vigorous cycling — and, in some cases, prostate cancer. The marker is sensitive but not specific: it flags that something is changing, not what.

What a result can tell you

A rapid screening result gives you an early, private read on whether your PSA sits above the commonly used threshold. That’s genuinely useful information for a group of men who statistically delay checkups: it converts a vague worry into a specific, answerable question for a doctor.

What it can’t tell you

An elevated PSA does not mean cancer — most elevations have benign causes — and a normal PSA doesn’t fully rule it out. Medical bodies recommend that PSA screening decisions be made individually with a clinician, weighing age, family history, and personal preference. Take any elevated result to a provider for proper measurement and follow-up; don’t interpret it alone.