Evaluation of kaolin-activated thromboelastography and sample stability in healthy horses

Thromboelastography is an accurate alternative to routine coagulation testing for the monitoring of haemostasis. However, its use in equine medicine is limited not only by the lack of reference interval values for kaolin-activated citrated samples, but also by the limited accessibility of the test for field practitioners within the 2-hour storage time recommended by the manufacturer. To address this issue, we here evaluated kaolin-activated thromboelastography using a TEG® 5000 Thrombelastograph® Hemostasis System in 36 healthy horses, and sample stability was evaluated at four timepoints post collection in seven horses. Reference values were established as follows: reaction-time 5.0-16.0 min, K-time (period in which the clot strength reaches 20 mm of amplitude) 1.1-5.2 min, α-angle (speed of fibrin cross-linking) 36.5-79.0°, maximal amplitude 44.5-69.7 mm, fibrinolysis 30 minutes after maximal amplitude was reached 0.0-2.8%. During storage, the trends in the changes of values were similar for most parameters, and values remained mostly within the reference intervals. Thromboelastography is thus useful in defining thrombohaemorrhagic complications in horses but can be sensitive to preanalytical factors and storage.