Аннотация:Chapter 1 covers the approaches to quantitative measurement of the spontaneous aggregation kinetics of red blood cells in whole blood samples and the biophysical and clinical importance of these measurements. It is shown that real-time measurement of the backscattered light intensity provides information on a number of important characteristics of blood related to the hemorhological status of the donor. Though there are a number of parameters influencing the aggregation and disaggregation measurements, statistically significant correlations with different diseases can be obtained that have high diagnostic value for clinicians. The relation of blood aggregation and sedimentation measurements is also discussed. It is shown that the new emerging modality of laser manipulation and trapping (laser tweezers) is very helpful when studying the individual features of interaction between cells, measuring the corresponding forces and the kinetics of cells aggregation and disaggregation.