Definition of factor VIII in US English:

factor VIII

(also factor eight)


  • A blood protein (a beta globulin) involved in clotting. A deficiency of this causes one of the main forms of hemophilia.

    • ‘It is a condition in which there is a either a quantitative or qualitative defect in the von Willebrand factor, a protein that is necessary to platelet adhesion and acts as a carrier protein for factor VIII.’
    • ‘Haemophilia is caused by a deficiency of factor eight which causes the blood to clot.’
    • ‘The disease is caused by deficient or defective blood coagulation proteins, known as factor VIII or IX.’
    • ‘These abnormalities in the immune system may explain the appearance of autoantibodies directed against factor VIII in patients with clonal disorders such as erythroleukemia, as well as myelofibrosis and myelodysplastic syndrome.’
    • ‘Another function of the von Willebrand factor is to carry the important clotting protein, called factor VIII, in the blood.’


factor VIII