Transcript Blood Typing

Health Occupations
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Antigens: foreign object, pathogen
Antibodies: proteins secreted by lymphocytes
Antibodies bond with antigens = lock and key
phenomenon
Antigen = lock
antibody = key
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Each person inherits 2 genes.
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Dominant genes
◦ Are A and B
◦ Shown as “I”
◦ EX:
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Recessive genes
◦ O
◦ Shown as “i”
◦ Ex:
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Blood type is determined by antigens on the
surface of RBC
A
◦ Only A antigens
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B
◦ Only B antigens
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AB
◦ Both A and B antigens
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O
◦ Neither A or B antigens
Your immune system has a tolerance against
it own antigens.
(you like your own antigens)
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EX: Antigen
A
type
A blood. It will
NOT form anti-A antibodies.
Blood Type
Antigens on RBC’s
Antibodies in Plasma
A
A
Anti - B
B
Recipient
D
O
N
O
R
Blood
Type
A
A
+
B
AB
O
B
AB
O
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Need to mix serum of the patient with the
blood cells of the donor.
If Type A gets matched with Type B then
antibodies will clump together
If this test is not done hemolysis (rupture of
blood cells) can occur
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Type O Blood
◦ Universal donor
 Because it lacks A and B antigens
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Type AB Blood
◦ Universal recipients because they lack anti-A and
anti-B antibodies.
 (they won’t attack new blood coming in)
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Found in RBC
Rh- : people who do not have antigens on
RBC
Rh+ : people who do have the antigen on RBC
About 85% of Americans are Rh+
If RH + blood is given to Rh- then the body
thinks it is an invading pathogen and starts to
form antibodies for the lock and key
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When an Rh- mother delivers an Rh+ baby,
some of the baby’s blood may contact the
blood of the mother
The mother’s blood then forms antibodies
against Rh+ RBC
If the mother has another Rh+ pregnancy the
antibodies will attack the baby’s blood
causing erythroblastosis fetalis.