F8 and hemophilia: The hemophilia severity is determined by the residual plasma FVIII activity (FVIII:C) and classified as severe (FVIII plasma activity below 1 IU/dL), moderate (FVIII plasma activity between 1 and 5 IU/dL), and mild (FVIII plasma activity between 5 and 40 IU/dL).