The PlateletWorks kit that measures clopidogrel resistance utilizes ADP-coated tubes. Clopidogrel inhibits platelet aggregation by binding to ADP receptors, blocking this mechanism from allowing fibrinogen linking. The change in platelet count due to activation and aggregation of functional platelets is measured using an electronic impedance-based cell counter.
The difference in the platelet count between samples one and two provides a direct measurement of platelet aggregation and is reported as percent aggregation. Platelets rendered inactive or non-functional by clopidogrel do not aggregate.
The percent platelet aggregation is then calculated:
- From the % Aggregation/Inhibition Chart supplied in the packaged tubes
- Using the Plateletworks calculation wheel
- Using the formula below