INR Blood Clotting Testing

A Top Ranked Manhattan M.D. Explains: What is an “INR” Test?

INR TestingThe INR blood clotting test is conducted to measure how long it takes the blood to clot. It is generally used to check for bleeding problems as well as to evaluate whether a prescribed medicine to prevent blood clots is working for the patient. This can be a very important test for some patients because abnormal prothrombin time can often be due to liver disease or injury or because of treatment with blood thinners.

A doctor may initiate this test to determine the cause of abnormal bleeding or bruising as well as to regularly check the patient on blood thinner treatment. The test also helps physicians check for low levels of blood clotting factors as well as low levels of Vitamin K.

Your Upper East Side doctor, Dr. Marina Gafanovich, can provide a more detailed explanation in person regarding an “INR” test, but essentially an “INR” test (internal normalized ratio test) is simply a test that measures the extrinsic pathway of blood coagulation in the human body.  The evaluator is attempting to derive the “prothrombin time” (PT) from tests performed against blood plasma.  This means that the blood that is drawn from your body must be separated into blood cells and blood plasma before the test can be performed.  This is done using citrate to bind the calcium within the blood and then entire vial is centrifuged to separate cells from plasma.  Once this has been performed, our staff will then add calcium to the plasma mixture so that it can “clot” and INR measurements can be taken.

INR Blood Test appointment

There are many reasons why New York physician, Dr. Gafanovich, may recommend tests of blood clotting to be performed.


Heart patients on warfarin may need to have monthly testing done to ensure the efficacy of the medication they are using to prevent heart problems.  Hemophiliacs by nature have issues that must be continually monitored.  Also, issues with blood clotting can be a sign of organ malfunction.

Please call us (212) 249-6218 to schedule your appointment with Dr. Marina Gafanovich, MD.