Thrombin-antithrombin complex ELISA kits are assays designed to detect the protein complex composed of thrombin and antithrombin, also known as TAT. Thrombin is a serine protease that plays a role in blood coagulation and haemostasis, while antithrombin is a small protein which acts as a protease inhibitor. TAT is formed in a 1:1 ratio of thrombin and antithrombin. The presence of increased TAT is indicative of excess thrombin production, usually due to coagulation from blood vessel rupture. TAT is used as a marker to measure thrombin levels as thrombin cannot be measured directly due to its short half-life. Visit the supplier page for more information about detection range and reactivity.