ABO & Rh
By: Kashif Nadeem Khokhar
History of ABO And Rh Groups
Austrian scholar Karl Landsteiner began to
work on this topic since 1900.
he drew the conclusion: Human blood group
Ludwik Hirszfeld and E. von Dungern
discovered the heritability of ABO blood
groups in 1910–11 , with Felix Bernstein
demonstrating the correct blood group
inheritance pattern of multiple alleles at one
locus in 1924 .
What Is The Use of Blood
Each person’s blood is different due to the
presence of antigens (markers) on the surface of
Erythrocytes (Red Blood Cells).
Before a person receives a blood transfusion, it
is important to do blood typing.
Doctor’s must be sure that the donated blood is
compatible with the recipients blood.
Mixing blood types can be very dangerous, even
deadly in some cases.
The ABO System:
How it Works
In the ABO blood system there are two
possible red blood cell markers(Antigens) (A
method by which cells identify themselves):
– Ex: A person with an A marker is said to have type A blood, a
person with a B marker will have type B blood.
Type A Blood
Type A blood produces anti-B antibodies
that will attack type B blood.
A person with type A blood may only
donate their blood to another person with
type A blood or someone who has type AB
Type B Blood
Type B blood has the presence of anti-A
antibodies that will attack type A blood.
A person with type B blood can only
donate blood to another person with type
B blood or someone who has type AB
Type AB Blood
Type AB blood has BOTH markers
present, and does not contain ANY
For this reason type AB blood is
considered the Universal Recipient .
– Since type AB blood has no antibodies
against the other blood types, a person with
type AB blood can receive any type of blood if
needed, but may only donate blood to other
type AB recipients.
Type O Blood
Type O blood has neither an A or a B marker
and contains both anti-A AND anti-B antibodies.
Because type O blood does not have either
marker, it will not react with anti-A or anti-B
antibodies, So, a person with type O blood may
donate blood to any other blood types. For this
reason type O blood is known as the Universal
Type O will attack all other blood types (A,B, &
AB) so a person with type O blood may only
receive blood from another person with type O
Diagram of how different blood
types may donate:
The Rh Factor
A person with the Rh factor on his or her red blood
cells is said to be Rh-positive (Rh+ ).
Since this person has the factor, he or she will not
make anti-Rh antibodies.
A person without the Rh factor on their red blood
cells is said to be Rh-Negative (Rh- ).
This person WILL produce anti-Rh antibodies.
Therefore, an Rh+ person may receive both an
(Rh+) and an (Rh-) transfusion, but an (Rh-) person
can only receive Rh- blood.
The Rh factor was first identified in the blood
of a rhesus monkey. Also called
Rhesus factor .
If an Rh_
person receives Rh+ blood,
hemolysis and anemia occur.
Rh factor is very important, specially in
If mother is Rh- and the fetus is Rh+, A
condition called Erythroblastosis Fetalis
occurs, which can cause fetal death.
It is important to immunize Rh-negative
mothers after their first pregnancy to guard
against future Rh incompatibility reactions.
Immediately after childbirth, anti-Rh antibody
(RhoGAM) is injected into the mother. ( also
known as Antibody D).
Immunization must be repeated after each
pregnancy, including ectopic pregnancies
Blood Donor & Recipient