Coagulation factor XI

General Information

Coagulation factor XI, the same antihemophilic factor C, or Rosenthal factor, is a glycoprotein that is synthesized in the liver and megakaryocytes. It was first discovered in 1953 in a patient with severe bleeding after a tooth extraction. Its frequency is 1:100. Factor XI deficiency is a genetic pathology and is common in Ashkenazi Jews (with close relatives).

Coagulation factor XI (FXI) deficiency is transmitted in an autosomal recessive manner, that is, when both parents carry the defective gene. The frequency of detection is equal in both sexes.
FXI plays an important role in the coagulation cascade leading to thrombus formation. It stimulates the production of more thrombin and the protein that converts fibrinogen to fibrin, which helps maintain the clot.
Less intensive bleeding is characteristic of deficiency of factor XI or Rosenthal than in deficiency of hemophilic factors A and B. In addition, the intensity of bleeding often does not correspond to the plasma level of factor XI. Spontaneous hemorrhages are rare. Oral antifibrinolytic therapy provides good control of bleeding from the mucous membranes (menorrhagia) and is also sufficient to stop bleeding caused by tooth extraction.
In patients with autoimmune disorders, very rarely, although sometimes, antibodies against factor XI are detected.
In coagulation factor XI deficiency, the coagulogram shows a prolongation of the activated partial thromboplastin time (APTT), on the background of a rapid time and a normal indicator of thrombin time.

When should we do the research?
Prolonged bleeding initiated by trauma or surgery
Bleeding from the nose
Hematuria (blood component in urine)
Meno-metrorrhagia
Retinal hemorrhage

advance preparation: The study is performed on an empty stomach

Research material: venous blood

Reference norms:
70 - 130%
1-15 weeks of pregnancy: 70-130%
16-40 weeks of pregnancy: 70-150%