Factor VIII furotin ne a cikin jini wanda ke taka muhimmiyar rawa a cikin tsarin daskarewar jini. Musamman, Factor VIII wani abu ne na coagulation wanda ke aiki tare da wasu sunadaran don samar da gudan jini da dakatar da zubar jini. Hakanan an san shi azaman maganin antihemophilic ko von Willebrand factor. Rashin gazawar Factor VIII na iya haifar da matsalar zubar jini da ake kira hemophilia A.