Cancer & Tumor Marker guides

What total PSA measures, how to read age-adjusted results, and why velocity over time matters more than any single reading.

Learn how PSA plus free PSA refines prostate screening decisions.

Prostate-specific antigen is a protein enzyme made almost exclusively by the prostate’s glandular cells. It belongs to the kallikrein family of serine proteases (KLK3) and is normally secreted into seminal fluid. Most PSA remains within the ejaculate, but a small fraction passes through the prostate ducts and surrounding tissue into the bloodstream. Available at 2,000+ lab locations and at-home (select states). See FAQs below

Free PSA is the portion of prostate-specific antigen in the bloodstream that is not attached to other proteins. Prostate-specific antigen (PSA) is an enzyme made by prostate gland cells and released mainly into semen; in scientific terms it is a serine protease in the kallikrein family (kallikrein-related peptidase 3, KLK3). Available at 2,000+ lab locations and at-home (select states). See FAQs below

Your PSA biomarker test reveals more than just prostate cancer risk, it's a window into prostate health, inflammation, and aging patterns that most men overlook.

Your LDH level reveals cellular damage across your body, but interpreting "high" depends on context, symptoms, and related biomarkers.

This tumor marker test is associated with more than just cancer monitoring, it's a window into inflammation, tissue health, and treatment progress tracking.

This inflammatory marker reveals critical information about intestinal health and potential malignancy that blood tests often miss.

High TPO antibodies signal your immune system attacking your thyroid, but they're not a cancer marker.