Immunohematology
- Science of immune reactions relating blood transfusion.
- Transfusion adverse reactions: immune, infection, allergy etc.
- Fatal transfusion reactions still occur.
- WBC, Plt: HLA Ag, difficult to match. More reactions.
- RBC: No HLA Ag, only major blood groups – easy to match.
- 30+ blood group systems, >330 antigens !
- Only ABO & Rh are clinically significant. (Others MN, Kell, Duffy, P etc.)
- Naturally occurring strong IgM antibodies in ABO system.
- Common blood group O+ve, rare AB-ve.
- Landsteiner Law: When a person has a blood group antigen, corresponding antibody is absent from plasma.
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💡 ABO system based on H antigen (precursor). if not modified = O. if modified will be A/B
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💡 Rh system based on C, D and E antigens. non functional denoted as lower case. only D antigen is strong and clinically significant therefore Rh D = pos, d = negative
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💡 Bombay blood group has anti H antibodies, clinically presents as O
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