Hand-Cranked Microfluidic Chip Tests Blood Type and Hematocrit in One Minute

Essential blood metrics outside the clinical laboratory

When treating severe trauma, emergency medical staff need to confirm two critical parameters: a patient's blood group to ensure transfusion compatibility, and their hematocrit, which reflects the proportion of red blood cells to detect anemia or active blood loss. Conventional hospital testing relies on bulky diagnostic machines requiring electrical grids and trained technicians, resources that are typically unavailable in ambulances, disaster zones, or rural facilities. To address this logistical gap, a team led by inventor and distinguished professor Chien-Fu Chen at the Institute of Applied Mechanics at National Taiwan University designed an electricity-free testing platform, detailing their findings in Biosensors and Bioelectronics.

“Our goal is to bring two essential blood tests out of the laboratory and into the hands of first responders, with no electricity or specialized training needed”

— Chien-Fu Chen, distinguished professor at National Taiwan University

How the micro-slit separation mechanism functions

The diagnostic system consists of a compact plastic chip loaded with approximately three microliters of blood from a standard finger prick. Operating a manual crank spins the chip, generating centrifugal force that propels the fluid through winding microfluidic channels prefilled with reagents for A, B, and Rh blood groups. When a specific blood antigen matches the corresponding reagent, red blood cells aggregate into clumps. At the terminal point of each channel, a micro-slit measuring approximately one-tenth the width of a human hair arrests the agglutinated cell clusters while allowing single, unreacted cells to pass. The trapped red cells produce a visible red band indicating blood type, while the physical length of the band against an integrated scale measures the hematocrit.

Accuracy and performance under field conditions

The research team evaluated the technical reliability of the platform using 21 hospital patient samples. Comparative assessments demonstrated that the optical readouts closely aligned with data generated by automated hospital laboratory analyzers. Furthermore, experimental tests confirmed that variations in manual cranking speed did not compromise the accuracy of the diagnostic readout. Completed in roughly one minute, the workflow turns the portable setup into an accessible medical device designed to support frontline healthcare workers. Chen highlighted that the broader innovation seeks to move essential diagnostics away from stationary lab benches directly into disaster-response operations, demonstrating how this practical invention could soon advance through the patent process to reach field medics worldwide.

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