Causes of high and low factor VIII (antihemophilic globulin A)

Approximately one third of hemophilia A "carriers" have factor VIII activity of 25 to 49%. In patients with a mild form and "carriers" of hemophilia A, clinical manifestations of the disease occur only after injuries and surgical interventions.

The minimum hemostatic level of factor VIII activity in the blood for performing operations is 25%; at a lower content, the risk of developing postoperative bleeding is extremely high. The minimum hemostatic level of factor VIII activity in the blood to stop bleeding is 15-20%; at a lower content, stopping bleeding without administering factor VIII to the patient is impossible. In von Willebrand disease, the minimum hemostatic level of factor VIII activity to stop bleeding and perform surgery is 25%.

In DIC syndrome, starting from stage II, a distinct decrease in factor VIII activity is noted due to consumption coagulopathy. Severe liver disease can lead to a decrease in factor VIII content in the blood. Factor VIII content decreases in von Willebrand disease, as well as in the presence of specific AT to factor VIII.

Factor VIII activity increases significantly after splenectomy.

In clinical practice, it is very important to differentiate hemophilia and von Willebrand disease.

Coagulogram indicators in hemophilia and von Willebrand disease

Indicator	Hemophilia	Von Willebrand disease
Blood clotting time	Increased	Norm
Duration of bleeding	Norm	Increased
Platelet aggregation with ristocetin	Norm	Reduced
Prothrombin time	Norm	Norm
APTT	Increased	Norm
Thrombin time	Norm	Norm
Fibrinogen	Norm	Norm