ABO advanced Mandatory Revision Questions and Verified Answers 2024

Forward Type - Looking for unknown antigen on RBC, use known antibody (Antisera), Agglutination indicates the presence of antigen, determines the ABO group Reverse Type - Use Known antigen (reagent red cells) to detect--Unknown antibody in plasma, agglutination indicates the presence of antibody, confirms the ABO group (most of the time, ~2% discrepancy) ABO subgroups: "A" main subgroups - Type "A" may be broken down into 2 main subgroups: A1 and A2 What % of A people have an unexpected reverse reaction that doesn't match forward reaction - 1% of the 40% that are type A A1 phenotype has which antigens - A1 and A (H) A2 phenotype has which antigens - A only (NO such thing as A2 antigen) (H) Quantitative A1 v. A2: A1 - A1 has higher concentration of A (in addition to having A1 antigen) Quantitative: A1 v A2: A2 - A2 has fewer A antigens and Higher concentration of H Qualitative: A1 v A2 - Linear (A) vs. branched (A1) forms of the same antigen Group AB can also be subdivided into different subgroups - A1B...A1, A, B, (H) antigens. A2B.....A and B, (H) antigens