A protein in the blood plasma that is essential for the coagulation of blood and is converted to fibrin by the action of thrombin in the presence of ionized calcium.

• 纤维蛋白，原一种为凝血必不可少的存在于血浆中的蛋白质，而且当存在电离出的钙时能通过凝血酶作用转化为（血）纤维蛋白。