ABO Blood Groups - Subgroups & Discrepancies

• What forward and reverse typing may occur for type A2 blood

  see picture

  
• How to distinguish A1 from A2

  • other subgroups: A3, Ax, Am, and Ael
• Serious donor reactions can occur in other A subgropus, such as Am, Ax, and Ael
• Discrepancies in ABO Grouping

  • ABO grouping is confirmed by the matching of the forward and reverse typing (cells and serum)
  • When they don't match up, you have an ABO discrepancy
  • In an emergency, give type O until you can resolve this discrepancy
• common causes of discrepancies:

  • clerical error - improper ID, improper recording of reactions
  • technical error
  • failure to follow manufacturer directions
  • contaminated or expired reagents
  • improper cell concentrations
  • failure to add reagents/sample, improper amounts
  • improper centrifugation
• Cold reactive antibodies

  • will see panagglutination, everything is agglutinated, patients own cells, all the reagent cells, other peoples' cells
  • after blood is drawn, it cools down and starts to agglutinate with itself
  • the issue is usually anti-I
• weak or absent antigens

  • can be due to subgroups of A or B
  • weakening due to leukemia