Major Blood Group system Flashcards
Most important blood group system in transfusion practice
ABO blood group system
ABO frequency distribution for Whites
O-45%, A-40%, B-11%, AB-4%
ABO frequency distribution for Blacks
O-50%, A-26%, B-20%, AB-4%
ABO frequency distribution for Asians
O-40%, A-28%, B-27%, AB-5%
Landsteiner’s law regarding blood groups
Antigen on RBC determines the blood group, and the corresponding antibody is not found in the individual’s serum.
Meaning of ABO blood group system numbering 001 003
First three digits represent the blood group, last three digits represent the antigen expressed.
Antigens location in the blood
Surface of red blood cells
Antibodies location in the blood
In serum or plasma
ABO antibodies classification
Naturally occurring, predominantly IgM
Production initiation and peak age of ABO antibodies
Initiated at birth, detectable titers peak at 5-10 years
ABO antibodies in Type O
Anti-A, Anti-B, Anti-AB
ABO antibodies in Type A
Anti-B
ABO antibodies in Type B
Anti-A
ABO antibodies in Type AB
None
Most frequently performed tests in blood bank
Forward typing and Reverse typing
Forward typing process
Using known sources of commercial anti-A, anti-B to detect on individual’s RBCs
Reverse typing process
Detecting ABO in patient’s serum using known reagent red cell suspension
Reagents used in reverse typing
4-5% red cell suspension (Tomato red suspension)
Reverse typing exception
Not required in infants less than 4 months old
General rule for adding reagents in blood typing
Drop first clear solute, then add RBC to ensure both antibody and antigen are added
Type I precursor substance linkage
Terminal galactose attached to N-acetylglucosamine in a beta 1 → 3 linkage
Type II precursor substance linkage
Terminal galactose attached to N-acetylglucosamine in a beta 1 → 4 linkage
Gene controlling ABH antigens on RBC membrane
H gene
Gene indirectly controlling ABH antigens in secretions
SE gene
Secretion test principle
Involves agglutination inhibition reaction
Secretion test patient sample
Saliva
Secretion test reagents
Reagent 1: Antisera; Reagent 2: Known cells
Alleles of the Se gene and their implications:
SeSe or Sese: Secretor; sese: Non-secretor
Unexpected reactions in ABO typing can occur due to
Extra positive reaction or weak/missing reaction in forward and reverse grouping
ABO discrepancy encountered resolution
Results must be recorded, but ABO type interpretation must be delayed until resolved
ABO discrepancy unresolved,
Transfuse group O blood
Primary cause of hemolytic disease of the fetus and the newborn (HDFN) and hemolytic transfusion reactions (HTR)
Rh blood group
Second most important phenotypically related to Rh blood group
LW
Landsteiner and Wiener discovered Rh antibody agglutination in
Guinea pigs, rabbits, and Rhesus macaque monkeys
Fisher Race Rh blood group system
DCE
Wiener Rh blood group system
Rh-Hr
Rosenfield Rh blood group system
Numerical
ISBT 004 001 Fisher Race, Wiener, Rosenfield
ISBT 004 001: D, Rh0, Rh1
ISBT 004 002 Fisher Race, Wiener, Rosenfield
ISBT 004 002: C, Rh’, Rh2
ISBT 004 003 Fisher Race, Wiener, Rosenfield
ISBT 004 003: E, Rh’’, Rh3
ISBT 004 004 Fisher Race, Wiener, Rosenfield
ISBT 004 004: c, hr’, Rh4
ISBT 004 005 Fisher Race, Wiener, Rosenfield
ISBT 004 005: e, hr’, Rh5