-ABO blood groups are based on presence or absence of two agglutinogens (A and B) on surface of RBC's
-blood may contain performed anti-A or anti-B antibodies (agglutinins)
ABO blood groups:
-AB: no plasma antibodies, can receive A, B, AB, and O blood, "universal recipient"
-B: anti-A, can receive B and O blood
-A: anti-B, can receive A and O blood
-O: no RBC antigens, anti-A and anti-B, can receive O blood "universal donor"
-RH blood type is either positive or negative, you either have it or you don't (most common blood type)