Currently, there is no single haemostasis laboratory test that has the capacity to accurately illustrate the clinical effects of procoagulant or
anticoagulant interventions. Although the time course of
thrombin generation in plasma and the endogenous
thrombin potential (ETP) may be useful coagulation parameters, clotting involves components other than
thrombin (e.g. platelets,
fibrinogen). The continuous coagulation profiles of thrombelastography may provide a more accurate reflection of in vivo biology, covering initiation, development and final clot strength during whole
blood clot formation. This method has helped to clarify the mechanism of action of whole
blood clot formation, demonstrating the differences from clotting in plasma, and the importance of platelets and
tissue factor titrations. It has also been used to investigate hypocoagulation (in
haemophilia A, rare coagulation disorders,
anticoagulant therapy and dilutional coagulopathy), hypercoagulation and the ex vivo testing of haemostatic interventions. Thrombelastography has been shown to reflect the clinical efficacy of activated
prothrombin complex concentrate (aPCC) and recombinant
activated factor VII (
rFVIIa) in patients with
haemophilia A with inhibitors and in patients with acquired
haemophilia. Overall, tailoring laboratory assays to illustrate and correlate with clinical phenotypes is essential for effective coagulation monitoring. Applying an algorithm of preoperative, perioperative and postoperative tests, including thrombelastography, may enable physicians to achieve this.