Antithrombin III Unit Converter

Antithrombin III (often called simply antithrombin) is a protein in your blood that helps prevent unwanted clotting. It works by inactivating key clotting enzymes, most importantly thrombin and Factor Xa.

It belongs to a family of proteins called serine protease inhibitors (serpins). Antithrombin circulates continuously in the blood, acting as a natural brake on the clotting cascade to keep blood flowing smoothly.

Heparin, a commonly used blood thinner, works primarily by boosting antithrombin's activity up to 1,000-fold. Without adequate antithrombin, heparin cannot function effectively.

Antithrombin III is produced by the liver and circulates in the blood with a half-life of approximately three days.