Attempts to standardize platelet aggregation measurements: simplified screening tests

We present a standardized measurement of collagen and ADP-induced platelet aggregation with the help of a personal computer. The calculator improves the recording of measurements and the automatic calculation of parameters to define the strength of aggregation in various aggregation phases, as well as aggregation and disaggregation velocities. The dose-effect relationships between aggregants and five calculated parameters after addition of ADP and four after addition of collagen are demonstrated in the light of measurements taken in 40 healthy persons. Comparison of these measurements with those of 8 volunteers 24 h after they had taken 250 mg of acetylsalicylic acid and those of of 5 patients with typical illnesses associated with hypo- and hyperaggregability shows that analysis of the aggregation with two reagent concentrations (1, 2 and 4 micrograms/ml collagen, 1, 2 and 4 mumols/ml ADP) and the resulting values allow one to distinguish between normal, hypo- and hyperaggregable platelets.