Computerized thromboelastography of wild-type and transgenic mice blood: the effect of hematocrit and platelet concentration. Computerized thromboelastography was used to investigate clot formation. Native whole blood from wild-type (dashed lines) and transgenic (solid lines) mice was analyzed and typical traces of the different age groups are shown (A; n = 4-6). Clot strength was reduced as early as 1 month in transgenic mice and further declined with age compared with wild-type controls. The erythrocyte concentration was increased in blood from transgenic mice and, at the same time, the concentration of platelets was decreased. To characterize the effect on the thromboelastogram of the erythrocyte concentration separate from the effect of the platelet concentration, experiments were performed where the concentration of one cell type was kept constant while the concentration of the other was varied. Increasing the hematocrit level when the platelet concentration was kept at 1000 (103/μL) (B;n = 3) resulted in a marked and progressive reduction of clot strength. When the hematocrit value was kept constant at 0.40 and the platelet concentration was varied (C;n = 3), a small reduction of clot strength with decreasing platelet concentrations was found; wt indicates wild-type; tg, transgenic; m, month; Hct, hematocrit; Plt, platelet number (103/μL).
