Viscoelastic testing: Transforming hemostasis management in patients in the medical intensive care unit

Table 1 Significance of key parameters used in rotational thromboelastometry and thromboelastography

Parameter on ROTEM	Parameter on TEG	Definition	Significance
CT	Reaction time	Time to 2 mm clot firmness amplitude	Reflects coagulation factor activity and thrombin generation
Clot formation time	Kinetic time	Time from 2 mm to 20 mm clot firmness amplitude	Reflects fibrin polymerization, stabilization of the clot with platelets and factor XIII
α angle	α angle	Angle between the baseline and a tangent to the clotting curve through the 2 mm point	Reflects fibrin polymerization, stabilization of the clot with platelets and factor XIII
MCF	MA	The MA reached during the test	Reflects clot strength depending on platelets, fibrinogen, factor XIII
Lysis index at 30 minutes, 45 minutes, 60 minutes after CT	Lysis index at 30 minutes, 60 minutes after MA (Ly30, 60)	The residual clot firmness at 30 minutes, 45 minutes, 60 minutes after CT (ROTEM) in percentage of MCF. The reduction in clot firmness at 30 minutes, 60 minutes after MA (TEG) in percentage of MA	Reflects clot lysis depending on fibrinolytic activators or inhibitors, factor XIII, and platelet-mediated clot retraction

CT: Clotting time; MA: Maximum amplitude; MCF: Maximum clot firmness; ROTEM: Rotational thromboelastometry; TEG: Thromboelastography.