Erythrocyte sedimentation rate III tube diameter dependence in saline solution

Abstract

Erythrocyte sedimentation rate was measured in a physiological saline solution as a function of both the tube diameter d and the initial suspension length ${\mathit{ı}}_0$ . All the sedimentation curves in the vertical tubes were found to overlap over the range 1 mm < d < 7 mm and 100 mm < ${\mathit{ı}}_0$ < 330 mm, within the precision of 8 %. The sedimentation curves in the tilted tubes fit well to an exponential equation of $$\mathit{ı}=\mathrm{a}[1-exp\mathrm{(}-\mathrm{bt}\mathrm{)}]\mathrm{,}$$ where ı and t are the medium length along the tube and the elapsed time from sample injection respectively: At fixed tilt angle θ and ${\mathit{ı}}_0$ . a was roughly constant and b was roughly proportional to l/d, while at fixed θ and d, a was linearly proportional to to and b was constant. The initial slope $\mathrm{ESR}\mathrm{(}\mathit{\theta }\mathrm{)}={\mathrm{(}\mathrm{d}\mathit{ı}\mathrm{/}\mathrm{dt}\mathrm{)}}_{\mathrm{t}\to 0}=\mathrm{ab}$ was represented by a unique straight line as a function of ${\mathit{ı}}_0$ /d for each fixed tilt angle. The experimental results were compared with some recent theories.