A comparison of the Thrombelastograph and the ROTEM

Elastic modulus-based assessment of hemostasis in clinical and research settings has been conducted for nearly 60 years. Two systems utilizing this technology include the Thrombelastograph (Haemoscope Corporation, Niles, Illinois, USA) and the ROTEM (Pentapharm GmbH, Munich, Germany). The study goal was to compare the Thrombelastograph and the ROTEM to determine whether differences in data could be detected. Plasma (n = 8 per condition) was not activated (native); was celite-activated, hypocoagulable by dilution with hydroxyethyl starch; was celite-activated, normal; and was celite-activated, hypercoagulable by addition of fibrinogen. Equivalent ratios of plasma mixture to CaCl2 were maintained between the Thrombelastograph and ROTEM systems. Data collected included the reaction time, angle, maximum amplitude and maximum elastic modulus. The ROTEM system generated significantly (P<0.05) smaller reaction time (mean +/- SD, 459 +/- 39 versus 788 +/- 94 s) and greater angle (60.1 +/- 5.3 versus 46.4 +/- 4.6 degrees ), maximum amplitude (27.6 +/- 1.6 versus 24.4 +/- 1.4 mm) and maximum elastic modulus (1911 +/- 152 versus 1616 +/- 121 dynes/cm2) values with native plasma compared with the Thrombelastograph. Celite-activation tended to attenuate differences between the two systems. In conclusion, a comparison of the Thrombelastograph and the ROTEM with similar samples demonstrated clinically significant differences in the data generated without exogenous activation. Given these data and the differences in proprietary activator, divergent results are expected, perhaps affecting clinical decision-making.