Platelet function testing in atherothrombotic disease

Platelet function testing was introduced more than a century ago with the invention of bleeding time; a test which has now been replaced by more accurate methods. Light transmittance aggregometry is traditionally regarded as the gold standard for evaluating platelet function. However, lately the position of light transmittance aggregometry has been challenged by a panel of new instruments. Aspirin and P2Y12-inhibitors are antiplatelet drugs used for secondary prevention of cardiovascular disease. However, an increasing recognition of the fact that not all patients respond adequately to these agents has prompted a focus on individualising antiplatelet treatment. Platelet function testing enables the detection of patients with high on-treatment platelet reactivity and facilitates individually tailored antiplatelet therapy, yet platelet function tests have still not been adopted into routine clinical practice. The present review outlines key milestones of the development of platelet function testing and provides an up-to-date overview of currently available tests and important studies evaluating their strengths and limitations in a clinical context.