Updated: May 17, 2021
Short background about INR
A PT/INR test helps find out if your blood is clotting normally. It also checks to see if a medicine that prevents blood clots is working the way it should.
In healthy people an INR of 1.1 or below is considered normal. An INR range of 2.0 to 3.0 is generally an effective therapeutic range for people taking warfarin for disorders such as atrial fibrillation or a blood clot in the leg or lung.
What causes high INR levels?
A high INR level can happen when you take warfarin (Coumadin). Warfarin helps prevent blood clots. To do this, it slows the amount of time it takes for your blood to clot. This raises your INR level.
What happens if INR is high?
The higher your PT or INR, the longer your blood takes to clot. An elevated PT or INR means your blood is taking longer to clot than your healthcare provider believes is healthy for you. When your PT or INR is too high, you have an increased risk of bleeding.
What happens if INR is low?
A low INR result means your blood is 'not thin enough' or coagulates too easily and puts you at risk of developing a blood clot.
How often should warfarin be monitored?
The INR should be checked at least four times during the first week of therapy and then less frequently, depending on the stability of the INR. In general, a missed dose of warfarin is reflected in the INR within about 2 to 5 days after the dose is missed.
According to current guidelines, warfarin recipients should undergo international normalized ratio (INR) testing every 4 weeks.
Why CoaguChek XS for INR testing?
The CoaguChek® XS system is a convenient, portable and user-friendly instrument for monitoring warfarin therapy. It determines the INR value (International Normalized Ratio) from a drop of capillary whole blood – simple, precise and reliable.