ABO BLOOD GROUP SYSTEM

• H gene codes for the production of L-fucossyl transferase
• A gene codes for the production of N-acetylgalactosaminyltransferase
• B gene codes for the production of galactosyl transferase
• Immunodominant sugar in group A = N-acetylgalactosamine
• Immunodominant sugar in group B = D-galactose
• Immunodominant sugar in group O= L-fucose
• Anti-A1 Lectin- Dolichos biflorus
• Anti-B Lectin- Griffonia (previously Bandeiraea) simplicifolia
• Anti-H Lectin- Ulex europaeus.
• O > A2 > B > A2B > A1 > A1B
• Type I - Weak or Missing Antibodies
• A3 - Mixed field agglutination with anti-A and Anti-A,B
• Ax - Not agglutinated by anti-A but mostly agglutinated by antiA,B
• A end - Mixed field agglutination with anti-A and anti-A,B - but only a very small percentage (less than or equal to 10%) of RBCs agglutinate.
• Am - Not weak agglutination with anti-A or anti-A,B.
• Ay - Not agglutinated by ant-A or anti-A,B; does not produce anti-A1
• Ael- Not agglutinated by anti-A or anti-A,B; produces anti-A1
• B3 - Mixed field agglutination with anti-B and anti-A,B
• Bx - Weak agglutination with anti-B and anti-A,B
• Bm - Not agglutinated by anti-B or anti-A,B
• Bel - Not agglutinated by anti-B or anti-A,B; sometimes produces a weak anti-B.
• Type III - Plasma or Protein Abnormalities
• Type IV - Miscellaneous Causes
• Discrepancies are unexpected reactions which occurs during forward and reverse grouping