Laboratory analysis of response to aspirin therapy can play an important role in monitoring patients at high risk for adverse cardiac events.
There are two main test methods that are utilized to monitor aspirin response. The first is based upon platelet aggregation in vitro. This method measures platelet function and determines aspirin response based on clotting time results. Agonists are used. Platelets with impaired functionality result in increased clotting times. If the sample does not show the inhibition of platelet aggregation formation within the reference intervals defined for aspirin therapy, the individual may have a lessened response or be unresponsive to aspirin therapy.
The second method measures 11-dehydrothromboxane B2 in urine. High levels of 11-dehydrothromboxane B2 (a metabolic breakdown product of thromboxane A2) in the urine may indicate a lack of response to aspirin.
