Factor VIII (FVIII) is an essential clotting factor in the coagulation cascade. The lack of normal FVIII causes Hemophilia A, an inherited bleeding disorder. FVIII harvested from donated blood/blood plasma or recombinant FVIII can be given to hemophiliacs to restore hemostasis. Thus, FVIII is also known as Anti-Hemophilic Factor.

The human coagulation factor VIII is assayed by its biological activity as a cofactor in the activation of factor X by activated factor IX (factor IXa) in the presence of calcium ions and phospholipids. The assay consists of two consecutive steps: the factor VIII-dependent activation of factor X and the enzymatic cleavage of a chromogenic factor Xa substrate that can be quantified photometrically. Many commercial kits are available for this purpose.

The validity of this assay should be checked and the potency of a test preparation should be calculated with the usual statistical methods given in chapter 5.3 of the European Pharmacopoeia or in <1034> of the US Pharmacopeia. PLA 3.0 provides you with an easy and convenient approach for this purpose.