A micromethod to measure platelet aggregation and atp release by impedance

A standard electrode has been modified in order to detect platelet aggregation by impedance in small volumes of whole blood. The modified electrode was constructed to fit into a standard 0.5-ml cuvette normally employed for detecting platelet aggregation in platelet-rich plasma (PRP) on a Chrono-log Aggregometer (Haverford, PA). Whole blood samples were mixed 1:1 with saline and total volumes of 1 ml, 500 microl and 300 microl were tested. ATP release was recorded concurrently with aggregation by measuring the luminescence from the firefly luciferin-luciferase reaction. The modified electrode could detect aggregation in the 300- and 500-microl samples with the same efficiency as the 1-ml samples. ATP release in the 300- and 500-microl samples yielded equivalent levels of release as detected with the 1-ml samples. This electrode is well suited for evaluation of platelet function in research and clinical blood samples where only small volumes of blood are available.