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There are four main blood groups defined by the ABO system: 1  blood group A has A antigens on the red blood cells with anti-B antibodies in the plasma. 2  blood group B has B antigens with anti-A antibodies in the plasma. 3  blood group O has no antigens, but both anti-A and anti-B antibodies in the plasma.ntroduction. There are four main blood groups (types of blood): A, B, AB and O. Your blood group is determined by the genes you inherit from your parents.
Blood group: An inherited feature on the surface of the red blood cells. A series of related blood types constitutes a blood group system, such as the Rh or ABO system. The frequencies of the ABO and Rh blood types vary from population to population.In the US, the most common type is O+ (meaning O in the ABO system and positive in the Rh system), which is present in 37.4 percent of the population.he frequencies of the ABO and Rh blood types vary from population to population. In the US, the most common type is O+ (meaning O in the ABO system and positive in the Rh system), which is present in 37.4 percent of the population.