PT/INR Test

PT/INR Test

PT/INR test is a special blood test designed to give an idea about the coagulation status of a particular individual. But what does PT/INR Test shows? Many people don’t know that. Actually PT is “Prothrombin time” and INR is “International normalized ratio”. Prothrombin time measures the extrinsic path of blood coagulation. In PT/INR Test blood is collected to a tube containing sodium citrate. Then tissue factor is added and time taken to the sample to clot measured optically. As you can see in this PT/INR Test the test result depends on the methodology used and the quality of the tissue factor. So the PT/INR test result is specific to that particular laboratory. That’s why there is an INR part. INR takes the ratio between patient sample and the control sample. When it is added to the formula PT/INR Test results can be compared globally. PT/INR Test is usually perfomed for the patients on warfarin, Liver damage and vitamin K status. This test is the most sensitive and widely used method to determine the blood coagulation profile. After a prosthetic valve replacement of the heart is is almost always necessary to check the coagulation profile by PT/INR test. Some times it may be necessary to measure it after an myocardial infarction.