Approach to erythrocyte aggregation through erythrocyte sedimentation rate: application of a statistical model in pathology.

Erythrocyte sedimentation rate (ESR) is mainly used in clinical practice as a screening test for inflammatory diseases and sometimes in the follow-up of patients. However, ESR is highly dependent on erythrocyte aggregation. In this study, using a Sediscan (Becton) automatic device measuring the kinetics of ESR, these results are compared with the measurement of erythrocyte aggregation as determined by laser light backscattering (Erythroaggregometer Affibio). A series of 188 samples from in-patients were tested. Statistical analysis of 13 parameters indicates that 82% of ESR variance may be explained by fibrinogen level, haematocrit and a parameter characterizing erythrocyte aggregation: the aggregation index at 10 s. This correlation was then validated prospectively in 128 other patients and seems to be independent of the underlying disease. Thus ESR in combination with fibrinogen assay and haematocrit may be considered as a simple and economic method to assess erythrocyte aggregation.