Summary
A method to estimate the sensitivity of platelets to aggregation by ADP has been described.
Platelet-rich plasma was obtained from 8% trisodium citrate anticoagulated blood.
ADP in trishydroxymethylaminomethane buffered saline was prepared by serial two-fold
dilutions in concentrations of 2−1 through 2−18 mg/ml. Fifty μl each of platelet-rich plasma and ADP solution were mixed in a plastic
test tube and agitated for 1 min. Aggregation was observed utilizing a light microscope.
All procedures were performed at room temperature. The coefficient of variation in
one sample was 1.4% or less and the daily variation was slight in healthy male volunteers.
An advantage of this method is that it requires only a small amount of blood for the
performance of many tests.
In 105 healthy Japanese males, the sensitivity of platelets to ADP-induced aggregation
was positively correlated with age with a correlation coefficient of 0.824.
In the acute stage of thromboembolism of myocardial infarction or stroke, value of
platelet sensitivity to ADP-induced aggregation was significantly higher at the 0.05
to 0.01 confidence limits than in age-, and sex-matched controls.
