Aspirin irreversibly inhibits platelet cyclooxygenase-1 (COX-1). Aspirin sensitivity
can be measured easily by its inhibition of arachidonic acid (AA) -induced platelet
aggregation. Aspirin resistance has to be defined by its inability to inhibit COX-1.
By using this definition, aspirin resistance very likely does not exist. A specific
rapid laboratory test using either AA-induced platelet aggregation or AA-induced malondialdehyde
production in platelet-rich plasma is needed to test aspirin sensitivity. The reports
on so-called aspirin resistance are usually due to noncompliance of aspirin intake
or consumption of inadequate doses of aspirin. In addition, data generated from using
nonspecific platelet function tests have added confusion to this observed phenomenon
of aspirin resistance.
Aspirin - aspirin resistance - aggregometry - laboratory testing - COX-1 - arachidonic
acid - malondialdehyde