Whole blood prothrombin time using diluted tissue factor is shortened in spontaneous hypertensive rats

Clinical screening tests for blood coagulation that use plasma as samples c annot estimate the participation of platelets, leukocytes, and erythrocytes in blood coagulation system. We developed an assay to evaluate the total c oagulation ability of blood and whole blood prothrombin time (WPT) using th e principle of prothrombin time with the diluted-tissue factor as a trigger and a newly developed apparatus, STA, viscosity change detection system (e lectromagnetic clot detection). The activation of platelets by Ca ionophore shortened WPT and increased the expression of CD62P on the platelet surfac e. WPTs in citrated blood of spontaneous hypertensive rats (SHR) were signi ficantly shorter than those of controls, Wistar Kyoto rats (WKY), Plasma le vels of thrombin-antithrombin III (TAT) in SHR were significantly higher th an those of WKY, Moreover, WPT and TAT levels were significantly correlated , Based on these results, WPT was found to be useful to estimate the activa tion of blood coagulation in whole blood.