[Detection of platelet aggregates using light scattering].

Platelets play an important role in hemostasis and thrombosis. Evaluation of platelet function provides useful information on the diagnosis and cure of diseases associated with hemostasis and thrombosis. Among various platelet functions, platelet aggregometry is most widely used in clinical application. Platelet aggregation has been assessed by measuring the changes in the optical density of the platelet suspensions. However, this method has several shortcomings such as failure to detect the formation of small aggregates and lack of correlation between aggregate formation and changes in optical density. Thus, we have developed a new method of platelet aggregometry based on light scattering. This device emits laser beams against platelet aggregates and efficiently detects light scattering produced by these aggregates. The intensity and frequency of light scattering provides information as to the size and number of aggregates present in a limited area. By this method, we were able to determine several different modes of inhibitory effects on platelet aggregation. The high sensitivity of this method also allowed us to detect slight platelet activation, which had not been possible by the conventional method using changes in optical density. Clinical application of this method revealed frequent occurrence of spontaneous aggregation in diabetic patients and a close relationship between this phenomenon and diabetic complications.