International Normalized Ratio
The international normalized ratio (INR) is a standardized calculation based on your prothrombin time. It lets clotting results be compared reliably across different labs and testing methods.
INR is the standard way to report how long your blood takes to clot in a comparable form. It is especially important for people taking warfarin, where staying in a target range balances clotting and bleeding risks. It is interpreted together with the PT and your clinical situation.
A higher INR means blood is clotting more slowly, which raises the tendency toward bleeding. This may result from anticoagulant medication, liver problems, or vitamin K deficiency. Your clinician will interpret it in light of your medications and overall picture.
A lower INR means blood is clotting more quickly; in someone on a blood thinner, this may mean the effect is weaker than intended. Your clinician will interpret it based on why you are being monitored.
For people not on anticoagulants, an INR near 1.0 is typical. If you take warfarin, your clinician will set a specific therapeutic INR range for your situation and adjust your dose to keep you within it.
Sources
Educational context only, not medical advice or a diagnosis. Reference ranges vary by lab, age and sex; always discuss your results with a clinician.