A person taking the anticoagulant (blood thinner) Coumadin^® or “warfarin” should maintain an INR within the safe therapeutic range prescribed by their doctor. Most commonly patients will be prescribed a therapeutic range of (INR) 2.0 – 3.0 and patients with a mechanical heart valve will often have a therapeutic range that is higher than this.

A person NOT taking anticoagulants should have an INR range between 0.8 to 1.2.o.