PSA, Total
A protein made by the prostate, used to screen for and monitor prostate cancer.
| Typical reference range | below 4 ng/mL |
Ranges vary by laboratory, method, age and sex: always use the range printed on your own report. Why labs differ.
What it measures
Prostate-specific antigen is an enzyme produced by prostate cells that liquefies semen. A small amount leaks into the blood, increasing with prostate size, inflammation or cancer.
Why it matters
PSA is used in shared-decision screening for prostate cancer, typically from age 50 (earlier for higher-risk men), and to monitor men after treatment. The trend over time (PSA velocity) and density relative to prostate size add context.
What a high result can mean
Elevations occur with benign prostatic hyperplasia (enlargement), prostatitis, urinary infection, prostate cancer, recent ejaculation, vigorous cycling, prostate biopsy or catheterization, and testosterone therapy.
What a low result can mean
Low values are favorable. 5-alpha reductase inhibitors (finasteride, dutasteride) lower PSA by about 50%, so values are typically doubled for interpretation.
What affects the result
Avoid ejaculation for 48 hours and vigorous cycling for a couple of days before testing. Normal ranges increase with age (about 2.5 for men in their 40s up to 6.5 for men in their 70s). Free PSA percentage helps interpret values in the 4-10 range.
Units and conversion
Usually reported in ng/mL.
- From ug/L: multiply by 1 to get ng/mL
Also called on lab reports
PSA, Total PSA, Prostate Specific Antigen, Prostate-Specific Antigen, PSA, Serum, PSA Total, Prostate Specific Ag, PSA, Total, Screening
Related tests: Prostate
This page is educational and does not replace advice from a healthcare professional.