The degree of red blood cell aggregation on peripheral blood glass slides corresponds to inter-erythrocyte cohesive forces in laminar flow

Objective: To determine the degree of correlation between red blood cell (RBC) aggregation on peripheral blood glass slides (PBGS) as determined by image analysis and the inter-erythrocytic cohesive forces as determined in a computerized cell flow properties analyzer (CFA). Study design: RBC aggregation was assessed using both systems simultaneously in healthy volunteers, obese patients and hypercholesterolemic individuals before and following LDL apheresis. Results: A significant (r=0.5, p<0.001) correlation was noted between the flow-dependent average aggregate size (AAS) obtained in the CFA and the degree of RBC aggregation on peripheral blood glass slides. Moreover, the enhanced RBC aggregation on the slides was positively associated with the appearance of larger aggregates in the CFA (r=0.5, p<0.001) and inversely with the formation of smaller aggregates (r=-0.27, p<0.04). A similar reduction in RBC aggregation following LDL apheresis was noted in both systems. Conclusions: The phenomenon of RBC aggregation on peripheral blood glass slides is governed by significant inter-erythrocytic cohesive forces and is not a result of a mere coincidental superimposition of cells. The slide test offers a rapid and simple method of evaluating rheologically significant RBC aggregation, and may allow stratification of patients at risk for atherothrombosis.