Master Immunohematology: Advanced Transfusion Medicine MCQs

10 clinical MCQs in Blood Transfusion. A patient with a known anti-Jk(a) antibody requires an urgent transfusion. The current ant

Questions, Answers & Explanations

1. Q1. A patient with a known anti-Jk(a) antibody requires an urgent transfusion. The current antibody screen is negative. What is the most appropriate next step to ensure a safe transfusion?

   • Provide Jk(a) negative units even if the crossmatch is compatible.
   • Provide crossmatch-compatible units regardless of Jk(a) status.
   • Perform an elution on the patient's pre-transfusion sample.
   • Administer intravenous immunoglobulin (IVIG) prior to transfusion.

   Answer: Provide Jk(a) negative units even if the crossmatch is compatible.

   Explanation: Kidd antibodies can become undetectable over time, but the patient remains sensitized. A historic antibody must always be respected — always provide antigen-negative units regardless of current screen results.

2. Q2. In a patient with warm autoimmune hemolytic anemia (WAIHA) and a pan-reactive antibody screen, which method is used to detect underlying alloantibodies if the patient has been transfused in the last 3 months?

   • Autologous adsorption
   • Allogeneic adsorption using phenotype-matched cells
   • Acid elution
   • Saline replacement technique

   Answer: Allogeneic adsorption using phenotype-matched cells

   Explanation: Autologous adsorption can't be used in recently transfused patients (donor cells would adsorb the alloantibody too). Allogeneic adsorption with phenotype-matched cells removes the autoantibody while preserving detectable alloantibodies.

3. Q3. Which blood group system is most frequently associated with delayed hemolytic transfusion reactions that present with a rapid drop in hemoglobin but negative initial antibody screens?

   • Kell
   • Duffy
   • Kidd
   • MNS

   Answer: Kidd

   Explanation: The Kidd system is the classic cause of delayed hemolytic transfusion reactions. Antibodies fade quickly, screen negative, then surge after re-exposure causing rapid intravascular hemolysis.

4. Q4. A 32-year-old female experiences severe hypotension and bronchospasm within minutes of starting a red cell transfusion. She has a history of recurrent respiratory infections. What is the most likely underlying deficiency?

   • Haptoglobin deficiency
   • Selective IgA deficiency
   • C1 esterase inhibitor deficiency
   • Albumin deficiency

   Answer: Selective IgA deficiency

   Explanation: IgA-deficient patients can develop anti-IgA antibodies. Transfusion of blood products containing IgA triggers a severe anaphylactic reaction. Recurrent infections are a clue to the underlying immunodeficiency.

5. Q5. Which specific modification to blood products is required to prevent Transfusion-Associated Graft-versus-Host Disease (TA-GvHD) in an immunocompromised bone marrow transplant recipient?

   • Leukoreduction
   • Washing with saline
   • Irradiation
   • Volume reduction

   Answer: Irradiation

   Explanation: Irradiation inactivates donor T-lymphocytes, which are responsible for TA-GvHD. Leukoreduction reduces but does not eliminate T-cells — only gamma or X-ray irradiation reliably prevents TA-GvHD.

6. Q6. During a massive transfusion protocol, a patient develops ionized hypocalcemia. This is most likely a direct metabolic consequence of which preservative/anticoagulant used in blood storage?

   • Heparin
   • Sodium Citrate
   • Adenine
   • Dextrose

   Answer: Sodium Citrate

   Explanation: Sodium citrate is used as an anticoagulant in blood storage. It chelates (binds) free ionized calcium, causing hypocalcemia during massive transfusion when large volumes are infused rapidly.

7. Q7. A neonate requires an exchange transfusion for HDFN caused by anti-c. The mother is O positive, R1R1 (CDe/CDe). The infant is A positive, R1r (CDe/ce). What is the most appropriate blood type for the exchange?

   • O positive, c-negative (R1R1) RBCs
   • A positive, c-negative (R1R1) RBCs
   • O positive, c-positive (rr) RBCs
   • AB positive, c-negative (R1R1) RBCs

   Answer: O positive, c-negative (R1R1) RBCs

   Explanation: Blood must be c-negative to avoid destruction by maternal anti-c still circulating in the neonate. O type is chosen over A to be compatible with any residual maternal ABO antibodies. c-negative (R1R1) is essential.

8. Q8. TRALI is most commonly caused by antibodies in the donor plasma directed against which of the following in the recipient?

   • Red cell antigens
   • Platelet glycoproteins
   • HLA or Human Neutrophil Antigens (HNA)
   • Plasma proteins like albumin

   Answer: HLA or Human Neutrophil Antigens (HNA)

   Explanation: Donor anti-HLA or anti-HNA antibodies bind to recipient neutrophils, activating them in the pulmonary vasculature and causing the capillary leak that defines TRALI (acute lung injury within 6 hours of transfusion).

9. Q9. What is the shelf life of a unit of Red Blood Cells that has been 'opened' by entering the system for washing or aliquoting in an open system, if stored at 1-6°C?

   • 4 hours
   • 24 hours
   • 7 days
   • 42 days

   Answer: 24 hours

   Explanation: Once the sterile seal of a blood unit is broken (open system), the risk of bacterial contamination requires discarding the unit within 24 hours when stored at 1–6°C.

10. Q10. A patient is found to have the 'Bombay' phenotype (Oh). Which of the following statements regarding their transfusion needs is correct?

    • They can safely receive Type O negative blood.
    • They can receive any Rh-negative blood.
    • They can only receive blood from another Bombay phenotype donor.
    • They require H-substance neutralized plasma.

    Answer: They can only receive blood from another Bombay phenotype donor.

    Explanation: Bombay phenotype patients lack H antigen entirely and have anti-H, anti-A, and anti-B antibodies. They will hemolyze all standard blood including O negative. Only another Bombay phenotype donor is compatible.