Schematics of the blood filtration device. (a) Assembled chip shown with syringe for injecting patient blood sample. The syringe port can be oriented vertically such that the syringe is inserted into the device without requiring the operator to manually brace the device. (b) Expanded device illustrates details for each layer.
Collection of plasma from a device during testing at the National Hospital for Tropical Diseases, Hanoi, Vietnam.
Volume of plasma collected for the 34 devices tested. Initial raw blood volumes were 0.8–1 ml, with a maximum expected yield of 280 μl. Variability is largely due to the deviation in fluid properties between patient blood samples (i.e., viscosity), the manual plasma extraction process, and the inconsistencies of the hydrophilic coating inherent to individual devices.
Comparison between the red blood cell counts of the plasma filtered with the devices and separated using a centrifuge. The inset shows the red blood cell counts of the whole blood prior to filtration. The device outperformed the centrifuge machine in 31 out of 34 cases, with lower red blood cell counts. The device filtered out an average of 99.9% of the red blood cells.
Comparison between the white blood cell counts of the plasma filtered with the devices and separated using a centrifuge. The inset shows the white blood cell counts of the whole blood prior to filtration. The device filtered out an average of 96.9% of the white blood cells.
Comparison of the biochemistry testing results between plasma derived from the devices and the centrifuge for the four biomarkers, (a) ALT, (b) AST, (c) urea, and (d) creatinine. Reference ranges for the centrifuge are shown by the dashed lines, and reference ranges for the devices—scaled to accommodate adsorption levels averaged over all samples—are shown by dotted-dashed lines (scaled 63% for ALT, 87% for AST, 94% for urea, and 28% for creatinine). Urea and creatinine have two dashed lines and two dotted-dashed lines to represent the lower and upper values of their reference range and scaled range, respectively.
Volume of plasma required for tests commonly performed on hepatitis B patients at the National Hospital for Tropical Diseases.
Methods and test kits used for testing.
Reference ranges and test precision for biochemistry tests at the National Hospital for Tropical Diseases, Hanoi, Vietnam.
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