Blood Types Explained A, B, AB and O Red Cross Blood
Download Guide. There are four major blood groups determined by the presence or absence of two antigens, A and B, on the surface of red blood cells. In addition to the A and B antigens, there is a protein called the Rh factor, which can be either present (+) or absent (), creating the 8 most common blood types ( A+, A, B+, B, O+, O ...
WhatsApp)
