Factor VII activity and antigen

Factor VII (FVII) is an important element in the initiation of blood coagulation. When tissue factor (TF) is exposed to the blood, upon vascular injury or following monocyte activation, a one-to-one stoichiometric complex with FVII is formed; this constitutes the primary event of blood coagulation and will lead to the activation of FVII, through the cleavage of a single peptide bond located at Arg152-Ile153. The TF-FVIIa serves to activate factors IX (FIX), X (FX) and also FVII (autocatalytically). The TF-FVII pathway has the following features: