Thromboelastogram (TEG)
What it is and when to use it
Thromboelastography (TEG) is a whole‑blood, viscoelastic haemostatic assay that records the dynamic process of clot formation, strengthening and lysis. It integrates the contribution of clotting factors, fibrinogen, platelets and fibrinolysis and therefore provides a functional, bedside picture of haemostasis that conventional plasma tests (INR, APTT, platelet count) may not show.
TEG and the closely related ROTEM platform are recommended by NICE for detecting, managing and monitoring haemostasis during and after cardiac surgery when used by trained staff, and there is good evidence of benefit and cost‑effectiveness in cardiac and liver transplant surgery (NICE HTG348 / DG13). For major trauma and postpartum haemorrhage, NICE judged evidence insufficient for routine adoption at the time of the guidance; local protocols, trial participation and audit are encouraged where devices are used.
Clinical uses
- Rapid identification of haemostatic defects at the bedside.
- Guiding targeted haemostatic therapy during major bleeding and surgery.
- Predicting transfusion requirements (for example, MA in trauma).
- Monitoring response to haemostatic interventions.
Physiology and what the trace represents
A TEG trace records viscoelastic changes over time and maps loosely to the phases of the cell‑based model of haemostasis:
- Initiation (enzyme activation and thrombin generation).
- Amplification and propagation (fibrin formation and platelet activation).