Blood coagulation, also called blood clotting, is the term given to a complex series of reactions that results in the formation of a tightly knit meshwork at the site where a blood vessel has been severed. The ability of a body to stem the flow of blood following injury to blood vessel is vital to survival of the organism.

Coagulation is a complex process that involves blood cells called platelets, various coagulation factors that are circulating in the blood and blood vessels. When a blood vessel is cut open, the open end shrinks in size to limit the opening. Platelets are recruited to the site to plug the opening. Then, the various enzymatic coagulation factors in the blood plasma are activated, leading to the formation of fibrin. Fibrin is a strong, cross-linked protein that becomes an integral part...