Quantitative Hematocrit Measurement on a Pressure-Actuated Microfluidic Chip

In point-of-care diagnostics, hematocrit (HCT), which is the volume percentage of red blood cells in the whole blood sample, is closely related to human health status. Here, we developed a pressure-actuated, polydimethylsiloxane (PDMS) microfluidic chip for quantitative measurement of HCT. The narrowest part of its flow channel is 8 μm and acts as a constriction for blood cells, which can lead to retardance of blood flow in the chip. The amount of red blood cells has an influence on the transport time of passing through the constriction for the blood samples, so we can use the transport time to infer the HCT value. We found a linear calibration curve between blood transport time and HCT value, which showed a correlation coefficient (R2) of 0.9506 for blood samples with HCT ranging from 0.35 to 0.55. This microfluidic chip can provide the results of HCT measurement within 1 min, making it well-suited for point-of-care diagnostics.