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ABO Basics. Blood group antigens are actually sugars attached to the red blood cell. Antigens are “built” onto the red blood 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. ABO Basics.
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ABO Basics • Blood group antigens are actually sugars attached to the red blood cell. • Antigens are “built” onto the red blood 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.
ABO Basics • The immune system produces an antibody (protein) in the plasma (produced by white blood cells) for the antigen not present. • Antibodies recognize foreigners and destroy them. Antibody B destroys antigen B. • For example, blood type A has antigen A attached to the red blood cell and antibody B in their plasma. Therefore, if blood type B is injected into their systems, anti-B antibodies in their plasma will recognize it as an alien and destroy it.
Rh Factor • Another important antigen (antigen D) found on the surface of blood cells is the Rh factor. • Blood containing this antigen is said to be Rh positive (Rh+); blood lacking this antigen is said to be Rh negative (Rh-). • Production of antibody to D requires exposure to the antigen. • The D antigen is very immunogenic, ie, individuals exposed to it will very likely make an antibody to it. • For this reason all individuals are typed for D, if negative must receive Rh (D) negative blood.
RhDisease of the Neborn – How it Occurs • A) child is Rh+ and mother is Rh - • B) during pregnancy fetal Rh+rbc’s escape into maternal circulation • C) This causes the mother's immune system to make antibodies against the baby's red blood cells Rh (D) in future pregnancies. • D) Second pregnancy with Rh (D) pos child results in destruction of fetal D pos rbcs • This antibody response is called Rh sensitization and, depending on when it happens, can destroy the red blood cells of the baby before or after it is born. • If sensitization happens, a fetus or newborn can develop mild to severe problems (called Rh disease). In rare cases, if Rh disease is not treated, the fetus or newborn may die. • A woman with Rh-negative blood can get a shot of Rh immunoglobulin (such as RhoGAM) that almost always stops sensitization from occurring. Problems from Rh sensitization have become very rare since Rh immunoglobulin was developed.
Hemolysis • If an individual is transfused with an incompatible blood group destruction of the red blood cells will occur. • This may result in the death of the recipient.
Clumping • If a film remains uniform in appearance, there is no agglutination (clumping). • If the sample appears granular, agglutination has occurred.
When does the blood react? • Blood reacting to anti-A is group A. • Blood reacting to anti-B is group B. • Blood reacting to both anti-A and anti-B is group AB. • Blood not reacting to either anti-A or anti-B is group O. • Blood reacting to anti-Rh (D) is Rh+; Blood not reacting to anti-Rh (D) is Rh-
How common is your blood type? 46.1% 38.8% 11.1% 3.9%