Under normal circumstances, sialic acid on erythrocyte membrane is negatively charged to form zeta potential, which makes red blood cells repel each other, maintain suspension stability and settle very slowly. However, under pathological conditions, plasma fibrinogen or globulin increases, which leads to the decrease of zeat potential of red blood cells, which are easy to contact each other and become money-shaped. The total contact area between the aggregated red blood cells and blood is reduced, and the resistance of plasma is weakened, which accelerates the erythrocyte sedimentation rate, while albumin and glycoprotein can slow the erythrocyte sedimentation rate. In addition, blood lipids are related to ESR, cholesterol can accelerate ESR, and lecithin can slow ESR.
Under normal circumstances, ESR and plasma reflux resistance are generally balanced, and ESR is slow. In severe anemia, because the total area of red blood cells is reduced, the resistance to plasma is reduced, so the erythrocyte sedimentation rate is accelerated. On the contrary, the erythrocyte sedimentation rate of polycythemia slows down. The shape of red blood cells also has some influence on erythrocyte sedimentation rate. The larger the diameter and the smaller the thickness of red blood cells, the faster the erythrocyte sedimentation rate. Spherical red blood cells are not easy to form money, so the sedimentation rate of red blood cells is slow.