Factor VII is a 50kDa multi-domain, single chain plasma glycoprotein synthesized in the liver and having abnormal circulating concentration of between 400 and 600 ug/L. It is essential for blood coagulation. Factor VII is converted to the active, two chain, serine protease Factor VIIa through cleavage by thrombin, factor Xa, factor IXa or factor XIIa. Factor VIIa converts factor X to factor Xa, which in turn converts prothrombin to thrombin.