Platelet function tests for the monitoring of P2Y12 inhibitors

IMPORTANCE OF THE FIELD: The individual response to clopidogrel therapy is unpredictable, resulting in high on-treatment platelet reactivity in a substantial number of patients. Moreover, consistent findings across multiple investigations point out that a strong relationship exists between high on-treatment platelet reactivity and the occurrence of atherothrombotic events. AREAS COVERED IN THIS REVIEW: This paper describes the current available methods of platelet function evaluation, including their advantages and drawbacks, reviews the evidence for the relation between high on-treatment platelet reactivity and clinical outcome, and discusses data concerning the clinical implications of platelet function testing in patients treated with thienopyridine therapy. WHAT THE READER WILL GAIN: The reader will be introduced to platelet function testing and its clinical applicability. The reader will gain a better understanding of the techniques used and will learn how to interpret the numerous data on platelet function testing and clinical outcome. TAKE HOME MESSAGE: Although a growing body of evidence demonstrates the promising potential of platelet function tests in predicting atherothrombotic events post stenting, platelet function testing should not yet be used routinely, as adequate treatment of high on-treatment platelet reactivity is unknown.