Laboratory detection of 'aspirin resistance' : what test should we use (if any)?

Aspirin is widely used to decrease the risk of occlusive arterial events in patients at risk. It irreversibly inhibits the cyclooxygenase-1 (COX-1)-dependent synthesis of thromboxane A2 (TxA2), which is essential for the full aggregation response of platelets. In the last years, the issue of ‘aspirin resistance’ has been emphasized in the medical literature.1–4 Despite several studies published on this subject, its definition, diagnosis, prevalence, causes, and clinical consequences are still uncertain