Factor IX( Christmas factor)

Reference values ​​of the activity of factor IX in blood plasma - 60-140%.

Factor K( the Christmas factor, antihemophilic globulin B) belongs to the p-globulin, takes an active part in the first phase of plasma hemostasis. Factor IX is formed in the liver. Therefore, its content in the blood of patients with hepatitis, cirrhosis of the liver, as well as taking the derivatives of dicoumarin and indanediol is reduced. The development of factor IX is regulated by a gene located on chromosome X, at a locus, which is separated from the gene of the key enzyme for the synthesis of factor VIII.This gene mutates 7-10 times less frequently than the gene of the factor VIII synthesis enzyme. Because of this, hemophilia A is observed much more often( 87-94% of all patients with hemophilia) than hemophilia B( congenital factor IX deficiency - Christmas disease)( 8-15% of patients).

In the process of blood coagulation factor IX is not consumed.

Determination of factor IX plays a crucial role in the diagnosis of hemophilia B. The deficiency of factor IX is associated with the majority of bleeding in acute liver diseases.

Depending on the level of factor IX, the following clinical forms of hemophilia B are divided: extremely severe - factor IX concentration up to 1%;severe form - 1-2%;average severity - 2-5%;light form( subhemophilia) - 6-24%.In patients with mild form, clinical manifestations of the disease occur after trauma and surgical interventions. Definite difficulties are caused by the definition of the group of "carriers" of hemophilia B. This group can be assigned to women who, in repeated studies, found the content of factor IX below 40%, but above 24%.

The minimum hemostatic level of factor IX activity in the blood for operations is 20-25%, with a lower activity the risk of postoperative bleeding is extremely high. The minimal hemostatic level of factor IX in the blood for stopping bleeding is 10-15%, with a lower content the stopping of bleeding without the administration of factor IX is impossible [Ogston D., Bennett B., 1977].

Acquired deficiency of factor IX is found in diseases of the liver, Gaucher disease, in patients with nephrotic syndrome.