The erythrocyte sedimentation rate (ESR) is a widely used marker of inflammation, but the detailed mechanisms underlying the ESR remain unclear. We retrospectively collected laboratory data from our hospital's laboratory information system, and performed multiple linear regression analysis and correlation analysis to determine relationships between the ESR and other laboratory test parameters. The alpha-2, beta-2, and gamma fractions from serum protein electrophoresis, serum immunoglobulin (Ig) G, IgA, IgM, and complement C3 levels, plasma fibrinogen levels, and platelet count showed positive effects on the ESR; however, the serum albumin level showed negative effects. Since erythrocytes are negatively charged, an increase in positively charged proteins and a decrease in negatively charged albumin were suggested to increase the ESR. Notably, C-reactive protein (CRP) showed the third-strongest correlation with the ESR despite having no significant effect on the ESR. We also reviewed cases with discordant ESR and CRP levels to compare the disease profiles of high ESR/low CRP patients and low ESR/high CRP patients. The patients with high ESR/low CRP had a completely different disease profile from those with low ESR/high CRP. Since the ESR and CRP have different roles, they should be used as markers in a context-dependent manner.
Keywords: complement; erythrocyte sedimentation rate; fibrinogen; immunoglobulin; serum protein electrophoresis.