In an INR test, what does a higher number indicate?

In an INR (International Normalized Ratio) test, a higher number indicates a longer time for coagulation. INR is primarily used to monitor patients who are on anticoagulant medications, such as warfarin, to ensure they are within a therapeutic range that minimizes the risk of both thrombosis and bleeding.

A normal INR range for someone not on anticoagulants is typically around 1.0. When a patient is on anticoagulants, the therapeutic INR range may be between approximately 2.0 and 3.0, depending on the condition being treated. If the INR is significantly above this range, it indicates that blood is taking longer to clot than normal, which suggests an increased risk of bleeding rather than clotting.

Understanding this context is crucial for interpreting INR values correctly; a higher INR implies that the coagulation process is delayed, which is the opposite of a shortening coagulation time. This highlights the necessity for clinicians to manage anticoagulant therapy carefully to avoid complications associated with both increased clotting time and decreased clotting time.