Monitoring of red blood cell aggregability in a flow-chamber by computerized image analysis

A system for direct observation and video recording of red blood cells (RBC) under flow, and computerized analysis of their aggregability was constructed. A narrow-gap flow-chamber was designed, in which a blood sample is subjected to controllable flow. Software was developed to provide the RBC aggregate size distribution at different shear stresses. From the size distribution curves the average or median size (or any other percentile) of the aggregate population as a function of shear stress, as well as the shear stress required for complete disaggregation, can be derived. The kinetics of spontaneous aggregation, in stasis, from singly dispersed cells, as well as the disaggregation kinetics at varying shear stress, can be derived from temporal monitoring of the cells images. This system provides quantitative measures of RBC aggregability from direct visual monitoring of the aggregation and disaggregation processes.