what does an inr test for
Prothrombin Time and INR. Guide. Prothrombin time (PT) is a blood test that measures how long it takes blood to clot. A prothrombin time test can be used to check for bleeding problems. PT is also used to check whether medicine to prevent blood clots is working.A PT test may also be called an INR test.INR (international normalized ratio) stands for a way of standardizing the results of prothrombin time tests, no matter the testing method.So your doctor can understand results in the same way even when they come from different labs and different test methods.NR (international normalized ratio) stands for a way of standardizing the results of prothrombin time tests, no matter the testing method. So your doctor can understand results in the same way even when they come from different labs and different test methods.