Viscoelastic tests of hemostasis

Abstract

Viscoelastic tests (thromboelastography) were developed more than 60 years ago to assess bleeding and coagulation. Today, technical innovations and computer technology have brought these techniques to the bedside. Two types of point-of-care devices which assess viscoelastic changes in clotting whole blood are available on the market. They allow a dynamic assessment of the interaction between coagulation factors, inhibitors and cellular components during the clotting phase and subsequent lysis. Technical differences, as well as the specific coagulation activators used in each device, must be understood in order to correctly apply the results to clinical settings. This chapter reviews the technology related to viscoelastic exams, the tests and reagents used, as well as the differences between the devices available on the market.