Thromboelastography in Hematology

Thromboelastography uses a small whole blood sample placed in a heated cup with an oscillating pin to detect clot strength as fibrin and platelets create resistance, generating a tracing of reaction time, clot kinetics, alpha angle, maximum amplitude, and lysis at thirty minutes. ROTEM and TEG are two commercial systems with comparable principles but different parameter names and reagent activators.

Clinical applications include real time guidance of transfusion in trauma resuscitation, cardiopulmonary bypass weaning, liver transplantation, and postpartum hemorrhage by identifying specific defects in clotting factor activity, fibrinogen, platelet function, or hyperfibrinolysis within minutes. This allows targeted use of fresh frozen plasma, fibrinogen concentrate, platelets, or antifibrinolytic therapy rather than empiric massive transfusion protocols.

Limitations include lack of standardization across laboratories, sensitivity to sampling technique, inability to detect mild factor deficiencies or specific anticoagulant effects without additional reagents, and requirement for trained operators. Despite these constraints viscoelastic testing reduces blood product use, transfusion related lung injury, and mortality in selected high bleeding risk situations.