Which factor serves as the carrier for factor VIII?

Which factor serves as the carrier for factor VIII?

• A. Factor V
• B. Von Willebrand factor
• C. Factor IX
• D. Tissue factor

Answer: (B)

Von Willebrand factor serves as the carrier for factor VIII. It binds factor VIII in the circulation, stabilizing it and protecting it from proteolytic degradation, which lengthens factor VIII’s half-life and keeps it available at sites of injury. This partnership also ties factor VIII to platelets indirectly, since von Willebrand factor mediates platelet adhesion to damaged subendothelial surfaces. If von Willebrand factor is deficient or dysfunctional, factor VIII levels drop because it is no longer stabilized in circulation, leading to reduced coagulant activity. The other options are not carriers: Factor V is a separate coagulation factor; Factor IX is another intrinsic pathway factor; tissue factor initiates the extrinsic pathway. None of these act as a carrier for factor VIII.

Von Willebrand factor serves as the carrier for factor VIII. It binds factor VIII in the circulation, stabilizing it and protecting it from proteolytic degradation, which lengthens factor VIII’s half-life and keeps it available at sites of injury. This partnership also ties factor VIII to platelets indirectly, since von Willebrand factor mediates platelet adhesion to damaged subendothelial surfaces. If von Willebrand factor is deficient or dysfunctional, factor VIII levels drop because it is no longer stabilized in circulation, leading to reduced coagulant activity.

The other options are not carriers: Factor V is a separate coagulation factor; Factor IX is another intrinsic pathway factor; tissue factor initiates the extrinsic pathway. None of these act as a carrier for factor VIII.