Lec 13

• What is the main focus of the study material titled "IDENTIFICATION OF UNEXPECTED ALLOANTIBODIES"?

  Detection of atypical and unexpected antibodies in blood.
• What is the purpose of an antibody screen?

  To detect antibodies in patients requiring transfusions, pregnant women, blood donors, and patients with suspected transfusion reactions.
• What are the steps involved in the procedure of an antibody screen?

  1. Mix known RBCs with patient's serum.
  2. Add potentiator and incubate at 37°C.
  3. Spin and read results (if applicable).
  4. Wash three times with saline.
  5. Add AHG, spin, then read results.
  6. Read all negative results macroscopically (some facilities read microscopically).
  7. Add IgG-coated control cells to all tubes with a negative reaction at AHG.
  8. Spin and read for agglutination.
• What does any agglutination at any phase of testing indicate?

  It indicates an atypical or unexpected antibody.
• What is the purpose of an autocontrol in antibody screening?

  To detect autoantibodies using the patient's serum and RBCs.
• What are potentiators used for in antibody screening?

  To enhance antibody detection.
• Why is it important to research a patient's transfusion and antibody history before transfusion?

  To ensure safe transfusion practices and avoid adverse reactions.
• What is the purpose of an antibody panel in antibody identification?

  To identify alloantibodies detected in the patient's serum.
• How does the autocontrol help in determining the type of antibody?

  It determines if the antibody is an autoantibody or alloantibody.
• What does a room temperature reaction usually indicate regarding antibodies?

  It usually indicates an IgM antibody.
• What does a positive reaction in antibody identification indicate?

  A positive reaction should never be used to rule out antibodies; it should always be used in identification.
• How can the strength of reactions in antibody identification help in determining antibody specificity?

  Single-strength reactions usually indicate a single antibody, while various-strength reactions indicate multiple antibodies or dosage.
• What is the "Rule of Three" in antibody identification?

  If there are three cells with positive reactions and three cells with negative reactions, there is a 95% probability that the antibody is correctly identified.
• Why should testing red cells for antigen be performed only if no recent transfusions have occurred?

  To ensure accurate results, as recent transfusions may affect the antigen presence.
• What are the steps involved in solving an antibody panel?

  1. Autocontrol: Negative indicates an alloantibody exists only in serum.
  2. Phases: Determine if the antibody is IgG or IgM.
  3. Reaction Strength: Assess the strength of reactions.
  4. Ruling Out: Use negative reactions to rule out antibodies.
  5. Rule of Three: Ensure three positive and three negative reactions.
  6. Conclusion: Interpret the results based on the reactions observed.
• What does a negative autocontrol indicate in an antibody panel?

  It indicates that an alloantibody exists only in the serum and not on the patient’s red cells.
• What should be suspected if immediate-spin reactions are detected in an antibody panel?

  IgM antibodies such as anti-Lea, anti-Leb, anti-M, anti-N, anti-I, and anti-P1 should be suspected.
• How does the strength of reactions vary with antigen dosage in an antibody panel?

  The strength of the reaction varies with the antigen dosage, affecting the interpretation of results.
• What is the significance of observing three antigen-positive cells and seven antigen-negative cells in an antibody panel?

  It satisfies the "rule of three," indicating a high probability of correct antibody identification.
• What does the conclusion of an antibody panel indicate when anti-K and anti-Lua are not crossed out?

  It indicates that anti-K matches the reaction pattern and satisfies the rule of three.
• What does it mean if cell 7 in an antibody panel is homozygous for the K gene?

  It means that the reaction is stronger with this panel cell, showing dosage effects.