The document summarizes the ABO and Rh blood group systems. It explains that the ABO system categorizes blood into four main groups - A, B, AB, and O - based on the presence or absence of antigens A and B on red blood cells. The Rh system further distinguishes blood as Rh positive or negative based on the presence of the D antigen. The document outlines Karl Landsteiner's discovery of the ABO system in 1901 and the discovery of the Rh system in 1940. It notes that the ABO system is important for blood transfusions and describes the potential for Rh incompatibility between mother and fetus.

1. BLOOD GROUP SYSTEM

2. Introduction
 A blood group also called a Blood Type
 Classification of blood is based on the
presence or absence of inherited
antigenic substances on the surface of red
blood cells (RBCs).
 Blood group systems
◦ ABO blood group system
◦ Rh blood group system

3. Introduction
 Karl Landsteiner discovered the ABO Blood
Group System in 1901.
 The ABO blood group system is the most
important blood group system in human blood
transfusion.
 Determination of ABO blood groups depends
upon the immunological reaction between
antigen and antibody.

4. Landsteiner Rule:
 If an antigen is present on a patients red
blood cells (RBCs) the corresponding
antibody will NOT be present in the
patients plasma, under ‘normal
conditions’.

5. Based on the presence or absence of
antigen A and antigen B, blood is divided
into four groups:
1. A
2. B
3. AB
4. O

6. Cont..
 Blood having antigen A belongs to ‘A’
group. This blood has β-antibody in the
serum.
 Blood with antigen B and α-antibody
belongs to ‘B’ group.
 If both the antigens are present, blood
group is called ‘AB’ group and serum of
this group does not contain any antibody.
 If both antigens are absent, the blood
group is called ‘O’ group and both α and β
antibodies are present in the serum.

8.  It is the most important blood group
system after ABO.
 The Rh blood group system was
discovered in 1940 by Karl
Landsteiner and A.S.Weiner.
 It was first discovered in Rhesus monkey
and hence the name 'Rh factor’

9. Cont..
 The Rh blood group system consists of 49
defined blood group antigens among
which the five antigens D, C, c, E, and e are
the most important.
 The type D antigen is widely prevalent in
the population.
 Anyone who has this type of antigen is
said to be Rh positive, whereas a person
who does not have type D antigen is said
to be Rh negative.

10. Rh Incompatibility
Erythroblastosis fetalis
 Mother Rh negative and fetus Rh positive
 RBCs from the fetus can go into mothers
bloodstream through the placenta
 Rh negative mothers immune system treats
the Rh positive fetal cells as a foreign
substance and makes antibodies against them
 Theses anti Rh antibodies may cross the
placenta into the fetus where they destroy
the fetus’s circulation RBCs.

13. Blood Groups Compatibility