Effects of aggregating agents and of blood cells on the aggregation of whole blood by impedance technique

In this study the effects of different aggregating agents on platelet rich plasma (PRP) and whole blood (WB) aggregation, as determined by the optical and the impedance method, are evaluated. While the response of PRP to PAF, epinephrine and sodium arachidonate was comparable using the two methods, significantly greater amounts of collagen and ADP were required to obtain 50% aggregation of PRP. In addition, when the response of WB to the aggregation induced by different agents was compared to that of PRP (impedance method), no difference between WB and PRP was detected, with exception for ADP and sodium arachidonate induced aggregation. In vitro data on the aggregation of PRP induced by collagen and ADP in the presence of different concentrations of red cells and of white cells, suggest that WC and RC may affect PRP aggregation only in selected experimental conditions.