International normalized ratio (INR) which is a derivative of prothrombin time is a measurement of blood coagulation in the circulatory system. Both are used to determine the clotting rate of blood which can be affected by anticoagulant usage, liver damage and Vitamin K levels.

The preferred range of INR levels for patient on anticoagulation therapy is usually between 2 and 3, but it tends to vary depending on the patient's requirements.

The Government recommended the self-monitoring INR. According to them," Patient self-care is a key initiative in the NHS Plan for a patient centred health service and an important component in supporting people with long-term conditions." I mean High quality anticoagulation therapy can certainly be delivered through physicians’ offices and  anticoagulation clinics. For many patients these are good, effective, safe and convenient set-ups. However, for many people, INR self testing is also a good and attractive option. There are some powerful advantages of INR self testing over routine office-based care.