A new laser photometric technique for the measurement of erythrocyte aggregation and sedimentation kinetics.

The aggregation kinetics of erythrocytes is studied by using laser light scattering. Laser light is passed through a well mixed sample of blood and the forward-scattered light intensity is recorded continuously. During the process of aggregation and sedimentation under a gravitational field, erythrocytes are subjected to different orientations. The events of a single cell's movement, formation of aggregates and their sedimentation produce a variation in scattered-light intensity. The mean intensity variation that bears this information is effectively employed to arrive at the kinetics of single cells, one-dimensional aggregates and three-dimensional aggregates during sedimentation. In addition to this, the time intervals of different phases of aggregation and sedimentation are also measured. All these parameters are obtained for erythrocytes suspended in native plasma. Then, the results are compared with erythrocytes suspended in dextran (Dx) 70 and Dx 500.