Although recent investigations into the human blood groups have proceeded mainly at the molecular level, the RBC remains an exquisite model to study the expression of various genes and their related proteins. Although DNA may be informative, it may not always give meaningful information regarding protein expression on cell surfaces, which is where binding occurs. Because of their easy accessibility, RBCs will continue to be used as a major tool in the investigation of the causative agents for disease, whether they be viral, bacterial, or parasitic in nature.