BLOOD GROUPS

• The presence or absence of the A and B antigens produces four possible blood types: A, B, AB and O.

• A person with type A blood has red blood cells that carry only antigen A.

• A person with type B blood has red blood cells that carry only antigen B.

• A person with type AB blood has both antigens A and B.

• A person with type O blood has no antigen on their red blood cells.

The ABO has an odd feature. An individual is born with ANTIBODIES in blood plasma against red blood cells antigens that his or her blood antibodies that will bind to foreign red blood cells.

Blood GroupAntigens on

RBCsAntibodies in Plasma

A A Anti-B

B B Anti-A

AB A and B Neither

O Neither Anti-A and anti-B

People with the same type of blood donate blood to each other. People who have type O blood are called UNIVERSAL DONORS. Their blood can be given to anyone bacuse type O blood does not contain A or B antigens. A person with type AB blood can receive a transfusion of any type of blood because type

BLOOD TRANSFUSION

Blood Group

Antigens Antibodies Can give blood to

Can receive blood from

AB A and B None AB AB, A, B, 0

A A B A and AB A and 0

B B A B and AB B and 0

0 None A and B AB, A, B, 0 O

• AB blood does not have anti-a or anti-b antibodies. People with AB blood are called UNIVERSAL RECIPIENTS. In a transfusion, if the wrong blood groups are mixed, the red blood cells of the donor make clump together and break open because of the antigen-antibody reaction. This antigen-antibody reaction blocks the blood vessels and can cause kidney failure.

BLOOD TRANSFUSION

AGLUTINATION:

AGLUTINATION: If the wrong type of blood is given to a person, the red blood cells of the donor may clump together because of the antigen-antibody reaction. If it clogs the blood vessels and can cause kidney failure.

AGLUTINATION

Rh FACTORS

• Rh FACTORS: The Rh factors are another group of antigens found on the surface of red blood cells. About 85% of the human population have the Rh factors on red blood cells and are said to be RH positive, or Rh (+). The remaining 15% lack the Rh antigens and are said to be Rh negative, or Rh(-). Unlike the ABO system, antibodies to the Rh factors are not produced until the individual is exposed to Rh factors.

Erytroblastosis fetalis

• Erytroblastosis fetalis: Is a serious condition in which Rh (+) red blood cells of a fetus are destroyed by mother’s antibodies. It is caused by Rh (-) mother making anti-Rh antibodies which destroy the fetus’s Rh(+) red blood cells.