Catalog #: 221402
For Research Use Only
Chromogenic assay for the measurement of Factor VIII:C activity in human plasma or cocentrates using automatic or manual methods. Designed with the use of only human proteins for homogeneous enzymatic kinetics, in compliance with European Pharmacopea, offering two working ranges:
Low range (haemophilia A or von Willebrand disease): 0 - 25%
High range (recovery studies of Factor VIII:C concentrate infusions or thrombotic risk): 0 - 200%
Applications for diagnosing Factor VIII:C deficiencies (Hemophilia A or vWD), VIII:C concentrate infusion recovery studies, testing Factor VIII:C concentrates, or epidemiological studies for high concentrations of factor VIII:C related to an increased thrombotic risk.
Assay principle
Factor VIII:C is a chromogenic assay for testing the cofactor activity of Factor VIII:C.
When activated by thrombin, Factor VIII:C forms an enzymatic complex with Factor IXa, phospholipids and Calcium, which activates Factor X to Factor Xa.
In presence of a constant amount of Factor IXa, Phospholipids (PLPs) and Calcium, thrombin activated Factor VIII:C forms an enzymatic complex, which activates Factor X, supplied in the assay at a constant concentration and in excess, to Factor Xa. This activity is directly related to the amount of Factor VIII:C, which is the limiting factor in presence of a constant and in excess amount of Factor IXa. Generated Factor Xa is then exactly measured by its activity on a specific Factor Xa chromogenic substrate (SXa-11). Factor Xa cleaves the substrate and releases pNA. The amount of pNA generated is directly proportional to the Factor Xa activity.
Finally, there is a direct relationship between the amount of Factor VIII:C in the assayed sample and the Factor Xa activity generated, measured by the amount of pNA released, determined by color development at 405nm.
Thrombin Activated FVIII:C
Reagents -- Composition and Packaging
Human Factor X, lyophilized in presence of a fibrin polymerisation inhibitor. 2 vials.
Activation Reagent, Factor IXa (human), containing human thrombin, calcium and synthetic phospholipids, lyophilized. 2 vials.
SXa-11 Chomogenic substrate, specific for Factor Xa (SXa-11), lyophilized. 2 vials containing 6 mg of SXa-11 with a thrombin inhibitor.
Tris-BSA Buffer, ready to use, containing sodium azide (NaN3). 4 vials of 25 mL.