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.
Prothrombin Time (PT) is the screening test for. the extrinsic coagulation pathway. The assay is. based on the activation of the coagulation cascade. by the addition of thromboplastin to citrated. plasma at optimized calcium concentrations. PT is. sensitive to the vitamin K-dependent clotting.