In the emergency medical field, blood type (ABO type, Rh type) judgment test and crossmatching test for blood transfusion are indispensable, but at present, work by a technician is required.In addition, since the test takes more than 30 minutes, there is a concern that the start of blood transfusion to patients who have been urgently transported may be delayed.The development of quick and simple blood test technology is also required to improve the harsh working environment of medical staff.

　In recent years, many palm-sized microchips with microscale channels have been developed for blood tests, but they are difficult to handle.Therefore, the research group aimed at fully automating and speeding up blood test devices, and adopted "bubbles" that do not affect blood cell components when mixing blood with phosphate buffered saline (PBS) for dilution with a microchip.This is because if there is something that is immiscible in both solutions, mixing is promoted and the solution can be diluted efficiently.This resulted in complete homogenization of the diluent.

　As a result, we realized a mechanism to automatically dilute whole blood (blood that has not been separated) in the device, and succeeded in developing an analysis chip by examining the optimum conditions and structure.In the blood typing test, diluted blood reached the detection part in less than 1 minute after sample injection, and high-sensitivity judgment was possible in about 5 minutes.

　The newly developed blood group analysis chip for whole blood enables quick and simple blood group determination tests and crossmatch tests, so blood transfusion can be started quickly for patients with high urgency.It is also expected to contribute to the overall improvement of the quality of medical care by reducing the burden on medical staff and reducing costs.

Paper information:[Biomicro fluidics] Fully-automatic blood-typing chip exploiting bubbles for quick dilution and detection