What Is Prostate-Specific Antigen (PSA)?

What it is

PSA is a protein produced by prostate cells. It is normally present at low levels in blood but rises in prostate disease.

Why it matters

PSA is used in prostate cancer screening and monitoring; elevated levels prompt further evaluation.

Specimen

Whole blood / serum / plasma

Interpretation

Elevated = supports prostate cancer screening/monitoring.

Limitations

Rises in BPH and prostatitis; not diagnostic — use with imaging.

Related test: PSA Rapid Test — specimen: WB / S / P