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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-).
• For this reason all individuals are typed for D, if negative must receive Rh (D) negative blood.
Rh Disease 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. What blood type does the person in the right have?
Anti-A Results
Anti-B Results
Anti-RH Results
Blood Type
Positive (+)
Negative (-)
Positive (+)
Negative (-)
Positive (+)
Negative (-)
When does the blood react?
• Blood reacting to anti-A is group A because it has antigen A.
• Blood reacting to anti-B is group B because it has antigen B.
• Blood reacting to both anti-A and anti-B is group AB because it has both antigen A and B.
• Blood not reacting to either anti-A or anti-B is group O because it has no antigens.
• 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%
Blood Transfusion
Type You Can Give Blood To
You Can Receive Blood From
A A, AB A, O
O ALL O
B B, AB B, O
AB AB ALL
TYPE YOU CAN GIVE BLOOD TO
YOU CAN RECEIVE BLOOD FROM
Rh + + + or -Rh - + or - -
With Rh-/Rh+
Type You Can Give Blood To
You Can Receive Blood From
A+ A+ AB+ A+ A- O+ O-
O+ O+ A+ B+ AB+ O+ O-
B+ B+ AB+ B+ B- O+ O-
AB+ AB+ Everyone
A- A+ A- AB+ AB- A- O-
O- Everyone O-
B- B+ B- AB+ AB- B- O-
AB- AB+ AB- AB- A- B- O-
