Blood type, represented by the ABO and Rh(D) systems, is an immunoreactive feature of red blood cells (RBCs) that is determined by the antigenic moieties of sugar chains on the RBC surface. Determination of the blood type is especially important before blood transfusion, because transfusion of mismatched blood types can lead to hemolysis within patient’s blood vessels, which mediated by antibodies to the RBCs in blood plasma. Blood typing tests have traditionally been conducted manually, using techniques such as slide and tube agglutination tests. In the last 20–30 years, fully automated blood testing instruments have been developed and these are operational at blood centers and major hospitals. These instruments have advantages such as high throughput and high sensitivity. However, these advantages are somewhat offset by the large size and high cost of the instruments. These are major drawbacks, especially because on-site blood testing is an important requirement during an emergency or natural calamity. Development of a portable, low-cost, and sufficiently sensitive instrument for blood typing is therefore required to make on-site blood testing feasible.