A group of substances present in blood plasma that, under certain circumstances, undergo a series of chemical reactions leading to the conversion of blood from a liquid to a solid state (see blood clotting). Although they have specific names, most coagulation factors are referred to by an agreed set of Roman numerals (e.g. Factor VIII, Factor IX). Lack of any of these factors in the blood results in the inability of the blood to clot. See also haemophilia.
Subjects: Biological Sciences.