Chrono-Log instruments allow clinicians to establish a convenient therapeutic monitoring system. The Chrono-Log Whole Blood Ionised Calcium Lumi-Aggregation Systems allow the study of platelet function in whole blood in the presence of other cells. A micro-sample of blood is all that is required for measurement of aggregation and secretion, making the Chrono-Log System suitable for work with smaller sample volumes. The simultaneous measurements simplify, speed up and reduce the cost of analysis. All Chrono-Log whole blood systems can also be used with PRP is preferred.