Microrheology and protein chemistry of pathological red cell aggregation (blood sludge) studied in vitro 1 2

After decades of indirect studies about the phenomenon of pathological red cell aggregation (RCA), a method was developed which allows the photometric quantification of the kinetics of this most important hemorheological abnormality in viscometric flow in vitro. When compared to physiological RCA, the shear resistance is increased, the rouleaux are clumped due to side-to-side attachment and the aggregate grows in size during viscometric flow. Since only small volumes (5–10μl) are required for microrheological tests, the serum proteins responsible for pathological RCA in myeloma patients were analysed. So far, α ₂M and IgM could be identified as globulins producing RCA, however with distinct differences. The effect of high molecular weight Dextrans and of changes in hematocrit value are also studied.