Answer: Thrombin
Thrombin is the rapid-acting clot activator that can be used with STAT tests.
Thrombin also known as factor IIa is a serine protease that converts fibrinogen into fibrin in blood coagulation. The precursor of thrombin is prothrombin which is an inactive zymogen, is one of the several coagulation proteins containing γâ€carboxyglutamic acid which need vitamin K to be active.
Thrombin also activates procoagulant factors V, VIII, XI, and XIII. Additionally, when bound to thrombomodulin, it activates protein C, an anticoagulant zymogen.
Heparin, an anticoagulant lowers the activity of thrombin. It is used in conditions like pulmonary embolism, deep vein thrombosis, myocardial infarction and acute coronary syndrome.