Investigation of erythrocyte aggregation parameters of blood with low levels of fibrinogen by syllectometry

Abstract

An increase in fibrinogen, a coagulation factor in blood, enhances erythrocyte aggregation. However, no previous studies have fully investigated erythrocyte aggregation at low plasma fibrinogen concentrations (<150 mg/dL), which can be caused by severe hemorrhage and induce coagulopathy. The purpose of this study was to reveal erythrocyte aggregability at low fibrinogen concentrations that occur in severe hemorrhage by syllectometry, an optical method for measuring erythrocyte aggregation. Fifty-six blood samples with a fibrinogen concentration of 129.4 ± 88.3 mg/dL were prepared by mixing serum and plasma from 12 healthy volunteers, and the relationship between fibrinogen concentration and erythrocyte aggregation parameters obtained by syllectometry was examined. At low fibrinogen concentrations (<150 mg/dL), erythrocyte aggregation parameters (amplitude and aggregation index) decreased almost linearly with decreasing fibrinogen concentration (r = 0.808 and 0.745), and a time constant parameter (t_1/2) increased with decreasing fibrinogen concentration (r = –0.827), similar to previously reported results for normal to high fibrinogen concentrations. Relaxation time (t₀) increased exponentially with decreasing fibrinogen concentration (r = –0.608). These results suggest that erythrocyte aggregability decreases with decreasing fibrinogen concentration even at low fibrinogen levels that can cause coagulopathy, and that syllectometry can be used to detect decreases in fibrinogen.