what is an protime inr blood test
Prothrombin time. The prothrombin time (PT)âalong with its derived measures of prothrombin ratio (PR) and international normalized ratio (INR)âare assays evaluating the extrinsic pathway of coagulation. This test is also called ProTime INR and PT/INR. They are used to determine the clotting tendency of blood, in the measure of warfarin dosage, liver damage, and vitamin K status. PT measures factors I (fibrinogen), II (prothrombin), V, VII, and X.