Investigating the binding strength between subtypes red blood cells and their corresponding antibodies and rapidly differentiating subtypes in a microchannel

Identifying blood type is a routine procedure for blood transfusion, typically performed using forward and reverse typing methods. However, distinguishing blood subtypes remains a challenging task in clinical practice. This study proposes a novel approach to rapidly differentiate blood subtypes based on the distinct binding strengths between red blood cells (RBCs) and antibodies immobilized on a micro-channel surface. Different blood subtypes can be distinguished by measuring the ratio of RBCs before and after applying a shear force with a wash buffer. Experimental results demonstrate residual ratios of approximately 99.5%, 31.8–39.8%, 7.4–7.6%, and 10.0–11.1% for B, B₃ (including AB₃), B_el, and A_el types, respectively. Notably, this method makes it possible to differentiate subtypes with minimal surface antigens, such as B_el and A_el, within 15 min—significantly faster and less complex than the conventional adsorption–elution method used in clinical settings. This proposed approach offers a promising solution for rapidly differentiating rare blood subtypes.