The idea of putting blood into a person was a radical one when it was first attempted 350 years ago, but today, more than 15 million pints of blood are donated each year in the U.S. to be used in transfusions to over 5 million patients. ...

The Rh factor is a protein found on red blood cells; individuals with it are Rh positive, while those without are Rh negative, and it is inherited genetically. Rh incompatibility occurs during pregnancy if an Rh-negative mother carries...

Blood grouping is based on the presence of A and B antigens on red blood cells and their corresponding antibodies in the serum. Blood type A has A antigen and anti-B antibodies; type B has B antigen and anti-A; type AB has both antigens...