Factor XI (anti-hemophilic factor C)
Last reviewed: 23.04.2024
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The reference values (norm) of activity of factor XI in blood plasma are 65-135%.
Factor XI - anti-hemophilic factor C - glycoprotein. The active form of this factor (XIa) is formed with the participation of factors XIIa, Fletcher and Fitzgerald. Form XIa activates factor IX. With the deficiency of factor XI in the coagulogram, the coagulation time of the blood and APTT is prolonged.
In clinical practice, the determination of factor XI activity is mainly used to diagnose hemophilia C and in order to differentiate the deficiencies of factors XI and XII.
Congenital insufficiency of factor XI is called Rosental's disease, or hemophilia C. This is an autosomal recessive hereditary disease. Bleeding is mostly noted after injuries and surgeries.
The acquired deficiency of factor XI occurs mainly in DIC syndrome, anticoagulant therapy, intravenous injection of dextran.
The minimal haemostatic level of activity of factor XI in the blood for performing operations is 15-25%, with a lower activity the risk of postoperative bleeding is extremely high. The minimum haemostatic level of activity of factor XI in the blood for stopping bleeding is 5-15%, with a lower activity, stopping bleeding without the administration of XI factor is impossible.
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