T Watson P, MA, B; S Wattley SOC, PS; H Webster MS; J Webster E*, ME*, EL*, H; S White AD; J Whiteley PY, B, C; T Whiteley TT, TH; L Whitley BUS, SOC, MM; O Whittell P, MA, MS; C Whitwam PY, E/EL, ME*; A Whitworth MM; O Widdop PY*, SOC*, E*; C Wilcock PY, EL; M Wilford PY, ME, EL; I Wilinsky EL, PS, H, MM; B Wilkinson AD, ME.
Prothrombin time (PT) Prothrombin time (PT) is a blood test that measures the time it takes for the liquid portion (plasma) of your blood to clot. A related blood test is partial thromboplastin time (PTT). A blood sample is needed. If you are taking ant blood-thinning medicines, you will be watched for signs of bleeding.
Most people will be working with the drug Warfarin, also known as the brand name Coumadin. Warfarin is a time-tested drug, but it comes with some challenges. The biggest challenge of Warfarin is that you will have to monitor your blood. You do this through the PT-INR test (also known simply as the INR test). What is the PT-INR Test? PT is the abbreviation for âprothrombin time.â Prothrombin time is just a measure of how quickly your blood clots. INR is an abbreviation for âInternational Normalized Ratio.â This is the unit of measure thatâs used to determine how quickly your blood is clotting.