INR Levels and Warfarin
To help thin the blood and prevent a blood clot, a healthcare provider may prescribe an anticoagulant medication, such as warfarin (Coumadin®, Jantoven®). However, if the medicine is not taken as directed or is combined with certain foods or drugs, it may cause unsafe levels to accumulate in the blood. To help ensure your dosage is a safe and effective amount, a blood test to measure your international normalized ratio (INR) will be done on a fairly regular basis.
As your warfarin dosage increases, your INR levels will also increase. However, it is important that the INR value is not too high, as it might cause dangerous, uncontrollable bleeding. Also, it is important that this value is not too low, which could cause a blood clot or stroke.
(Click INR for more details on why it is important to check your INR levels while taking warfarin or certain other blood-thinning medications. This article also explains how this test is performed and why food or other drugs may affect your INR value.)