Elevated INR - Definition

December 2016


INR stands for "International Normalized Ratio" which is the ratio of the prothrombin time of the patient, and the prothrombin time reference in the normal individual. The PT is a test to identify the quality of blood clotting, which depends on many factors, the main one being the prothrombin. Prothrombin is synthesized by the liver in response to vitamin K. Thus, vitamin K is used as an anticoagulation treatment to increase the fluidity of the blood. INR enables the determination of the effectiveness of anticoagulant therapy with vitamin K antagonists (VKA). Specifically, when the ratio is 1, the anticoagulant effect is zero (this is the rate of a normal person, without treatment). Generally, the desired rate is located between 2 and 3, especially in the prevention of thromboembolic diseases such as in cardiac atrial fibrillation, or between 3 and 4 in patients at high risk, who have a heart valve, for instance. In case of an imbalance of treatment, the INR can rise to values higher than 4 and cause a risk of bleeding. Depending on the INR rate and the presence or absence of signs of bleeding, the treatment may vary from a simple dose adjustment to vitamin K antagonist therapy administered in an emergency.


Original article published by . Translated by Jeff. Latest update on December 11, 2013 at 04:42 AM by Jeff.
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