Analysis of sedimentation in human whole blood from its concentration profile of erythrocytes

Abstract

An apparatus for measuring the concentration profile of erythrocytes of human whole blood in settling tubes was devised. Experiments were made on the blood of five healthy male donors. A two-region moving boundary mathematical model for the erythrocyte sedimentation under unsteady state condition was developed for the settling process. A solution was obtained to give the expression of the erythrocyte concentration as a function of settling time and the distance along. the settling tube. From the mathematical model, two parameters, the mean sedimentation velocity and the diffusivity of erythrocytes, are the two main factors which control the shape of the erythrocyte concentration profile. A statistical method of parameter estimation was employed to determine these two parameters from five sets of concentration profiles experimentally secured. It was found that the diffusivity of erythrocyte varies between 1.5 × 10⁻⁴–2.0 × 10⁻³ cm²/sec. The range of variation of the mean sedimentation velocity is quite broad from 1.5 × 10⁻⁷ to 2.0 × 10⁻⁴ cm/sec among five blood samples. Also, the diffusivity of erythrocytes was found to be the predominant parameter which controls the erythrocyte concentration profile and the erythrocyte sedimentation rate (ESR).