This document summarizes the history and science of blood groups and blood typing. It discusses how Karl Landsteiner discovered the main blood groups (A, B, AB, and O) in 1901, which allowed blood transfusions to become safer. It describes the components of blood and explains that blood groups are determined by antigens (sugars) on red blood cells inherited from parents. Certain blood groups contain antibodies that can cause blood to clot if mixed with incompatible blood from a transfusion. Proper blood typing looks for antigens and antibodies to determine compatibility.

1. Dr.Shahida Baloch

2.  History of Blood Groups and Blood
Transfusions
•Experiments with blood transfusions have
been carried out for hundreds of years. Many
patients have died and it was not
until 1901, when the Austrian Karl Landsteiner
discovered human blood groups, that blood
transfusions became safer.
For this discovery he was awarded the Nobel
Prize in Physiology or Medicine in 1930

3.  An adult human has about 4–6 litres of blood
circulating in the body.
 Blood consists of several types of cells floating around
in a fluid called plasma.
 The red blood cells (RBCs)
contain haemoglobin, a protein that binds oxygen. RBCs
transport oxygen to, and remove carbon dioxide from
the tissues.
 The white blood cells
fight infection.
 The platelets
help the blood to clot, if you get a wound for example.
 The plasma
contains salts and various kinds of proteins.

4.  Blood group antigens are actually sugars (not
cheni) attached to the red blood cell.
 Antigens are “built” onto the red cell.
 Individuals inherit a gene which codes for
specific sugar(s) to be added to the red cell.
 The type of sugar added determines the
blood group.

5.  The differences in human blood are due to
the presence or absence of certain protein
molecules called antigens and antibodies.
 •The antigens are located on the surface of
the RBCs and the antibodies are in the blood
plasma.
 •The blood group you belong to depends on
what you have inherited from your parents.
What are the different blood groups?

6. Type A Blood
Type A
Antigen
Anti-B
Antibodies
Red Cells Plasma

7. Type B Blood
Type B
Antigen
Anti-A
Antibodies
Red Cells Plasma

8. Type AB Blood
Type B
Antigen
Neither Anti-A
or Anti-B
Antibodies
Red Cells Plasma
Type A
Antigen

9. Type O
Blood
Anti-A and
Anti-B
Antibodies
Red Cells
Plasma
Neither A nor B
Antigens

10. Blood Typing works by taking the antibodies
for each blood type and mixing them with a
drop of blood. Each drop of blood would be
mixed with a different anti-serum (anti-A,
anti-B and anti-Rh.

11. Pictures of what
actual slides
would look like
after addition of
the anti-serums

12. Blood Typing If we mix Anti- A serum with type A
blood there will be clumping of RBC’s as the antibodies
latch on the the antigens.
Type A Cells
Anti-A
serum
antibody

13. No clumping with Anti-B Antiserum
Type A Red Cell
Anti-B serum
antibody

14. Anti-A Anti-B Blood Group
NEG NEG O
POS NEG A
NEG POS B
POS POS AB

15. BLOOD GROUP ANTIGEN IN RBC
SURFACE
ANTIBODIES IN
SERUM
GENOTYPE
A A ANTI-B AA, AO
B B ANTI-A BB, BO
AB A & B NEITHER AB
O NEITHER NEITHER
ANTI-A AND
ANTI-B
OO
According to the ABO blood typing system there are
four different kinds of blood types.

16.  There are more than 20 genetically
determined blood group systems known
today
 The AB0 and Rhesus (Rh) systems are the
most important ones used for blood
transfusions.
 • Not all blood groups are compatible with
each other. Mixing incompatible blood
groups leads to blood clumping or
agglutination, which is dangerous for
individuals.

17. Thanks