Platelet Aggregation in whole Blood

A semi-micromethod for testing the aggregability of platelets in whole blood is described. Aggregation is induced with ADP at 37° C in 0,1 ml samples of citrated blood. At 30 seconds intervals aggregation is stopped and the number of nonaggregated platelets are determined. The main results as found in “normal” human donors (having received no drugs) are: 1) Platelet aggregation in whole blood is less dependent on the pH, the platelet number, the time elapse from blood sampling to aggregation test as compared with platelet aggregation in plasma (a.m. Born). 2) Disaggregation is only observed to a minor degree (after 180 seconds the maximal disaggregation amounts to 30% of the aggregated platelets). 3) Secondary aggregation is negligible. The technique is simple and can be used in the clinic without special equipments. The results are discussed.