A prothrombin time (PT) is a test used to help detect and diagnose a bleeding disorder or excessive clotting disorder; the international normalized ratio (INR) is calculated from a PT result and is used to monitor how well the blood-thinning medication (anticoagulant) warfarin (Coumadin®) is working to prevent bloodClick to see full answer. Simply so, what is the normal range for PT INR?Most of the time, results are given as what is called INR (international normalized ratio). If you are not taking blood thinning medicines, such as warfarin, the normal range for your PT results is: 11 to 13.5 seconds. INR of 0.8 to 1.1.Similarly, what is an INR blood test for? An INR test measures the time for your blood to clot. It is also known as prothrombin time, or PT. It is used to monitor blood-thinning medicines, which are also known as anticoagulants. The INR, or international normalised ratio, can also be used to check if you have a blood clotting problem. In this regard, what is the difference between PT and INR? PT and INR are both measures of how long it takes your blood to clot, expressed in two different ways. PT stands for prothrombin time. It is a measure in seconds of how long it takes your blood to clot. The INR is a formula that allows for differences between laboratories so that test results can be compared.What happens if prothrombin time is high?A typical PT result is 10 to 14 seconds. Higher than that means your blood is taking longer than normal to clot and may be a sign of many conditions, including: Bleeding or clotting disorder. Lack of vitamin K.