1 blood physiology practical 1 blood groups by: khulood hussein
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BLOOD PHYSIOLOGYPractical 1
BLOOD GROUPS
By: khulood HusseinBy: khulood Hussein
Phase II Medicine- Blood Module - March 2009
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Clinical significance of determination of blood groups
• At least 30 blood group system contaning 400 (Ag) have been found on the cell membrane of RBCs.
• These can cause Ag-Ab reaction if mixed with plasma that contain antibodies (Ab) against these Ag.
• 2 groups of blood system can cause transfusion reactions more than others: ABO and Rh systems.
Phase II Medicine- Blood Module - March 2009
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ABO Blood GroupsA and B Antigens- Agglutinogens
Phase II Medicine- Blood Module - March 2009
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ABO Blood GroupsRelative frequency of different blood types:
• O 47%
• A 41%
• B 9%
• AB 3%
Phase II Medicine- Blood Module - March 2009
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Agglutinins
Blood type Agglutinogen on RBC
Agglutinin in plasma
A A Anti-B
B B Anti-A
AB A and B None
O None Anti-A and Anti-B
Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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Rh Blood Type• If type D antigen is present on RBC Rh
+ve• Differences between ABO and Rh Ab?• Anti-Rh antibodies are not naturally
occurring Ab.• Previous exposure to Rh antigen is required.
• Rh +ve blood transfusion.• Rh –ve women pregnant with Rh +ve baby.
• Anti-Rh Ab can cross the placenta.
Phase II Medicine- Blood Module - March 2009
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Blood Grouping
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Blood grouping, showing agglutination of cells of the different blood types with anti-A or anti-B agglutinins in the sera
Red blood cell types
Anti-A serum Anti B serum
O - -
A + -
B - +
AB + +
Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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BLOOD TRANSFUSIONS
Phase II Medicine- Blood Module - March 2009
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Blood Transfusion
• Indications.• Types:
–Heterologus–Autologous
Phase II Medicine- Blood Module - March 2009
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Universal Donor.
• Most hospitals have available group O negative blood for use in extreme emergency situations.
• Group O negative is considered as universal donor.
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Transfusion Reactions resulting from mismatched blood types
• Agglutination and delayed hemolysis of donor’s RBC (or immediate intravascular hemolysis)→ Jaundice
Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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Diseases transmitted by blood transfusion
• Viral hepatitis
• HIV / AIDS
• Other transmissible diseases are syphilis, malaria.
What do you do to prevent this?
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Pre-transfusion Tests
• For a safe blood transfusion, the following tests are done:– Blood grouping
– Cross-matching
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X-matching• Once patient’s blood group is known, donor
blood of the same ABO and Rh type is selected.
• Possible donor RBC’s are mixed with the recipient’s serum. If no agglutination, no Ab in recipient blood will attack donor’s RBCs.
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Haemolytic Disease of the Newborn (HDN)
• Rh incompatibility Erythroblastosis Fetalis (HDN).
• Rh –ve lady marrying Rh+ve man.• If baby is Rh+ve, fetal RBC leaks to maternal
circulation during placental separation (delivery or abortion).
• Mother starts to make anti-Rh Ab.• Next pregnancy with Rh+ve baby anti-Rh Ab
pass to baby and cause agglutination and hemolysis of his RBC.
Phase II Medicine- Blood Module - March 2009
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Phase II Medicine- Blood Module - March 2009
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HDN• Clinical picture:
• Anemia→ Jaundice
• Kernicterus (mental
impairment due to precipitation of bilirubin in brain cells)
Phase II Medicine- Blood Module - March 2009
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Prevention• Anti-Rh gamma globulin (RhoGam)
injection given to Rh –ve mothers after delivery of Rh +ve baby.