Representative subsampling of sedimenting blood

Abstract

It is often necessary to extract a small amount of a suspension, such as blood, from a larger sample of the same material for the purposes of diagnostics, testing or imaging. A practical challenge is that blood sediments noticeably on the time scale of a few minutes, making a representative subsampling of the original sample challenging. Guided by experimental data, we develop a Kynch sedimentation model to discuss design considerations that ensure a representative subsampling of blood for the entire range of physiologically relevant hematocrit over a specified time of interest. Additionally, we show that this design may be modified to exploit the sedimentation and subsample either higher or lower hematocrit relative to that of the original sample. Thus, our method provides a simple tool to either concentrate or dilute small quantities of blood or other sedimenting suspensions.

Red Blood Cell Sedimentation Index Using Shear Stress of Blood Flow in Microfluidic Channel

“…However, conventional and/or modified ESR techniques adopt a vertical installation of a driving syringe or tube [ 19 ]. During the RBC sedimentation in the syringe, the RBCs become concentrated at the bottom position, and diluted at the sedimentation front [ 28 ]. When blood is suppled into the microfluidic channel from the blood syringe, the Hct tends to increase over time.…”

Sequential quantification of blood and diluent using red cell sedimentation-based separation and pressure-induced work in a microfluidic channel

“…16,17,33 RBC sedimentation is used to extract concentrated or diluted small amounts of blood samples from the original blood sample. 34 The variation in hematocrit substantially contributes to varying ESR (or RBC aggregation) and blood uidity. However, according to the previous methods, continuous quantication of RBC sedimentation over time is still considered challenging because the interface between plasma and RBC cannot be clearly observed during certain periods 35,36 or for blood samples with low hematocrit.…”