Measurement of the hematocrit using paper-based microfluidic devices

Abstract

The quantification of blood cells provides critical information about a patient's health status. Sophisticated analytical equipment, such as hematology analyzers, have been developed to perform these measurements, but limited-resource settings often lack the infrastructure required to purchase, operate, and maintain instrumentation. To address these practical challenges, paper-based microfluidic devices have emerged as a platform to develop diagnostic assays specifically for use at the point-of-care. To date, paper-based microfluidic devices have been used broadly in diagnostic assays that apply immunoassay, clinical chemistry, and electrochemistry techniques. The analysis of cells, however, has been largely overlooked. In this communication, we demonstrate a paper-based microfluidic device that enables the controlled transport of red blood cells (RBCs) and the measurement of the hematocrit-the ratio of RBC packed cell volume to total volume of whole blood. The properties of paper, device treatment, and device geometry affect the overall extent and reproducibility of transport of RBCs. Ultimately, we developed an inexpensive (US$0.03 per device) thermometer-styled device where the distance traveled by RBCs is proportional to the hematocrit. These results provide a foundation for the design of paper-based microfluidic devices that enable the separation and detection of cells in limited-resource settings.

Microfluidic-Based Biosensor for Blood Viscosity and Erythrocyte Sedimentation Rate Using Disposable Fluid Delivery System

“…A microfluidic device has several advantages, including small volume consumption, fast measurement, easy sample handling, high sensitivity, and disposability. Thus, it has been widely used to measure various biophysical properties of blood samples (i.e., blood viscosity [15], RBCs aggregation [16], RBCs deformability [17,18], and hematocrit [19]).…”

Point-of-Care Diagnostics: Recent Developments in a Connected Age

“…One device identified sickle-cell disorders 207 , with an alternate lateral flow test using monoclonal antibodies 208 . Another inexpensive paper-based test enabled controlled transport of red blood cells and measurement of hematocrit 209 . Paper sensors have also been used for enzyme quantification, such as a proof of concept quantitative estimation of α-amylase, an enzyme indicator of potential diseased states if abnormally high or low 210 .…”

Point-of-care diagnostics to improve maternal and neonatal health in low-resource settings

“…130 Impedance spectroscopy utilizes the principle that higher hematocrit levels will increase the current flow path between reference and working electrodes. With impedance spectroscopy, results could be achieved very quickly, and the reported cost is less than US $12.…”

“…The quantitative performance and reproducibility of this paper-based test has yet to be established. 130 Other methods of plasma separation have been previously reviewed. 28 …”