INR

International Normalized Ratio (INR) is a standardized measure of prothrombin time (PT), used to monitor the effectiveness of oral anticoagulant therapy (like warfarin/Coumadin). It corrects for variations between labs. For patients on warfarin, target INR ranges are therapeutic (e.g., 2.0-3.0). In individuals not on anticoagulants, the INR should be close to 1.0.