Should we integrate viscoelastic assays with standard coagulation screening?

The standard coagulation screening tests are useful to evaluate but do not give comprehensive assessment of haemostasis. These tests are based on the classification of coagulation systems into distinct extrinsic and intrinsic pathways—assessed by prothrombin time (PT) and activated partial thromboplastin time (APTT), respectively. However, the current evidence suggests that tissue factor activates the coagulation cascade, converting factor VII to VIIa—which in turn activates factor X and the intrinsic pathway via factor IX.1 Standard coagulation screening takes between 27 min and 77 min and these tests were not developed to predict bleeding or guide treatment.2 In an emergency, this delay may be crucial—hindering the clinicians with their decision-making process.

A detailed personal (surgery, dental extraction) and family history is the ideal initial screening for excluding a haemostatic disorder prior to the interventional and surgical procedures. However, in an emergency when the history is not available, it is difficult to assess the patient’s proneness for bleeding. Even when the coagulation screening test results are available, there are pitfalls in interpretation. When PT and APTT are within the normal range, it is assumed that the coagulation factors are above 30%, and that postprocedural bleeding should not be a major concern.3 However, a normal coagulation screen does not reflect a patient’s risk of bleeding during interventional procedures.4 Furthermore, abnormally prolonged APTT does not directly correlate with the severity of bleeding, and the replacement therapy may lead to the increased risk of thrombosis.5 The fibrinolytic system is not assessed by standard coagulation screening. Acquired hyperfibrinolysis is observed in a variety of clinical …