A novel modification of the Thrombelastograph assay, isolating platelet function, correlates with optical platelet aggregation

J Lab Clin Med. 2004 May;143(5):301-9. doi: 10.1016/j.lab.2004.01.011.


Flow cytometry, singlet platelet counting, and optical aggregation have been used to monitor clopidogrel and glycoprotein IIb/IIIa (GPIIb/IIIa) platelet antagonists. Optical aggregation is considered the gold standard, but neither it nor flow cytometry is convenient in larger-scale clinical studies or point-of-care systems. Singlet platelet counting, a point-of-care assay correlated with optical platelet aggregation, only provides a measurement of platelet function at a single point in time. The Thrombelastograph is used to assay whole blood for thrombin-generated maximal clot-shear elasticity, referred to as the maximal amplitude (MA). Although platelet dysfunction, thrombocytopenia, and the in vitro effect of strong inhibitors such as IIb/IIIa antagonists can be observed, with thrombin generation milder platelet inhibitors cannot be assessed. We modified the Thromboelastograph assay, using reptilase and factor XIIIa, to form a clot, without thrombin generation, in heparinized whole blood. The resulting clot MA is dependent on added platelet agonists such as ADP or arachidonic acid, is sensitive to platelet antagonists, and provides a continuous measure of platelet function more analogous and better correlated with optical aggregation. This novel modification of the Thromboelastograph assay should prove to be a useful point-of-care whole-blood assay with which to monitor the effects of GPIIb/IIIa, ADP, and thromboxane A(2)-receptor-inhibiting drugs in patients.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / pharmacology
  • Arachidonic Acid / pharmacology
  • Batroxobin / pharmacology
  • Blood Coagulation / drug effects
  • Blood Coagulation / physiology*
  • Blood Platelets / drug effects
  • Blood Platelets / physiology*
  • Dose-Response Relationship, Drug
  • Factor XIIIa / pharmacology
  • Hemostatics / pharmacology
  • Humans
  • Platelet Aggregation / physiology*
  • Platelet Aggregation Inhibitors / pharmacology
  • Point-of-Care Systems
  • Thrombelastography / methods*


  • Hemostatics
  • Platelet Aggregation Inhibitors
  • Arachidonic Acid
  • Adenosine Diphosphate
  • Factor XIIIa
  • Batroxobin