A microfluidic smart blood-typing device operated by finger actuation is reported. The blood-typing results are displayed by means of microfluidic channels with the letter and the symbol of the corresponding blood type. To facilitate the mixing of blood and reagents in the device, the two sample inlets are connected to a single actuation chamber. According to the agglutination aspect in the mixture, the fluids are directed to both microslit filter channels and bypass channels, or only to bypass channels. With this device, blood typing was successfully performed by seven button pushes, using less than 10 μL of blood within 30 s.

Professor Je-Kyun Park’s research team reported a finger-actuated microfluidic display for smart blood typing that directly displays whether a person has an A, B, AB, or O blood type, and whether the person is Rh positive or negative. The device is quick and easy to operate by repeatedly pushing a button on the device.

Blood typing is used as the first-line pretransfusion suitability test. Inaccurate blood typing of donor and recipient can result in a hemolytic transfusion reaction in a recipient. Simple blood typing has been performed by analyzing the agglutination patterns in the reaction between individual blood-typing reagents, but it can lead to human-induced error in the interpretation of agglutination patterns. To prevent this, fully automated blood-typing systems are used in blood banks and hospitals. Although these yield reliable results, they are not suitable for rapid blood typing of patients in urgent need of transfusion.

Figure 1. Photograph of smart blood-typing device, indicating Rh+ A.
Figure 1. Photograph of smart blood-typing device, indicating Rh+ A.

In this project, a simple and rapid blood-typing system was developed using a finger-actuated microfluidic device that displays the blood type by means of microfluidic channels. With use of a novel working principle of a finger-actuated microfluidic pump, the device demonstrates constant performance regardless of differences in end users. The device also allows parallel mixing of blood and reagents with a predesigned ratio. According to the agglutination patterns in each mixture, the fluidic paths are determined adaptively. By means of microfluidic channels, the determined fluidic paths present the results of the blood typing with letters. The blood type of an unknown sample can be determined simply by pushing the button within 30 s and using less than 10 μL of blood. It is notable that human-induced error during the manual interpretation of results can be prevented. Although it is demonstrated for the most common blood types (Rh and ABO), the system can be expanded to minor human blood-type systems (e.g. the Kell, Kidd, MNS, and Lewis systems).

Contact Information:
Juhwan Park, Je-Kyun Park Department of Bio and Brain Engineering, KAIST
Homepage: https://nanobio.kaist.ac.kr
E-mail: jekyun@kaist.ac.kr