Blood coagulation is a rapid series of complex processes by which haemostasis is initiated to prevent loss of blood by formation of a blood clot at the site of injury in a blood vessel.  Here a series of proteolytic reactions take place with a stepwise activation of coagulation factors, in the “Coagulation Cascade” which ultimately results in the formation of a fibrin clot.  Disorders of coagulation can lead to excessive bleeding (e.g. in Haemophilia A) or clotting (e.g. Deep Vein Thrombosis). NIBSC is involved in the control and standardisation of coagulation factors and related research.