The VisuLize Factor VIII ELISA Kit is intended to quantitatively measure factor VIII (F8) in human plasma and factor concentrates. The biological importance of factor VIII (F8) is demonstrated in Hemophilia A and those patients suspected of thrombophilia. The laboratory diagnosis of factor VIII (F8) deficiency in Hemophilia A typically involves quantitative determination of factor VIII’s functional activity. The use of this kit in conjunction with functional assays in the area of gene therapy, assessment of factor VIII (F8) concentrates, as well as distinguishing those patients with cross-reactive material will prove useful in the area of Hemophilia A. Additionally as documented in numerous studies, elevated levels of factor VIII (F8) is being recognized as a common risk of venous thrombosis¹, an area where Affinity’s Factor VIII ELISA Kit has utility.

This product is cleared for in vitro Diagnostic use by FDA, Health Canada and CE marked.  Available for sale in the United States, Canada and select European countries.

Product Code: FVIII-AG


  • Rapid sandwich ELISA to measure FVIII (F8) antigen (FVIII:Ag)
  • 1 hour 55 minutes total incubation time!
  • FVIII:Ag reported as International Units/ml traceable to WHO standard for FVIII antigen
  • Detection limit to 0.008 IU/ml FVIII:Ag (0.8%)
  • Includes normal and low controls
  • Shelf-life: 18 months


  • Quantification of FVIII (F8) in plasma and therapeutic concentrates
  • Diagnosis and characterization of Hemophilia A
  • Carrier testing for Hemophilia A
  • Thrombophilia screening

Species Cross Reactivity: View Chart

Product Datasheet: Factor VIII Complete Antigen ELISA kit - IVD

References: 1.O’Donnell J, Tuddenham EG, Manning R, Kemball-Cook G, Johnson D, Laffan M. High prevalence of elevated factor VIII levels in patients referred for thrombophilia screening: role of increased synthesis and relationship to the acute phase reaction. Thromb Haemost. 1997;77:825–828.

Description of Factor VIII (FVIII)

Factor VIII (formerly referred to as antihemophilic globulin and Factor VIII:C) is a large glycoprotein (320 kDa) that circulates in plasma at approximately 200 ng/ml. Synthesized in the liver, the majority of Factor VIII is cleaved during expression, resulting in a heterogeneous mixture of partially cleaved forms of FVIII ranging in size from 200-280 kDa. The FVIII is stabilized by association with von Willebrand Factor to form a FVIII-vWF complex required for the normal survival of FVIII in vivo (t1/2 of 8-12 hours).

F.VIII is a pro-cofactor that is activated through limited proteolysis by thrombin. In this process F.VIIIa dissociates from vWF to combine with activated Factor IX, calcium and a phospholipid surface where it is an essential cofactor in the assembly of the Factor X activator complex. Once dissociated from vWF, FVIIIa is susceptible to inactivation by activated Protein C and by non-enzymatic decay.

Hemophilia A is a congenital bleeding disorder resulting from an X-chromosome-linked deficiency of FVIII. The severity of the deficiency generally correlates with the severity of the disease. Some Hemophiliacs (~10%) produce a FVIII protein that is partially or totally inactive. The production of neutralizing antibodies to FVIII also occurs in 5-20% of Hemophiliacs 1-3.

References and Review

  1. Lollar P, Fay PJ, Fass DN; Factor VIII and Factor VIIIa. Methods in Enzymology, 222, pg 122, 1993.
  2. Hoyer, LW, Wyshock EG, Colman RW, in Hemostasis and Thrombosis, 3rd Edition, eds. RW Colman, J Hirsh, VJ Marder and EW Salzman, pp. 109-133, J.B. Lippincott Co., Philadelphia, 1994.
  3. Pittman DD, Kaufman RJ. Structure-Function Relationships of Factor VIII Elucidated through Recombinant DNA Technology. Thromb. Haemostas. 61:161-165, 1989.

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