Blood type (aka blood group) is the classification of blood based on the presence (or absence) of inherited antigens (combination of proteins, carbohydrates, glycoproteins, glycolipids) on the surface of RBC's.
There are 33 blood group systems, of which the 2 most important are:
ABO, which can be A, B, AB, or O. It is the
Rh factor, which can be Rh+ or Rh-
I see, so when we say someone has O positive blood, we mean that their blood type is O, but their Rhesus factor is Rh negative?
Yep, that it !
Many pregnant women will carry a fetus with a blood type different from their own, so the mother can form antibodies against fetal RBC's. These maternal antibodies can be IgG, which can cross the placenta and cause hemolysis of fetal RBC's, causing low fetal blood count, known as hemolytic disease of the newborn
Blood grouping, to detect blood group and Rh status