MLS Blood Banking & Transfusion Medicine 2 — Questions and Answers
Question 1: Which transfusion reaction presents with fever, chills, and rigors within 1–6 hours post-transfusion without evidence of hemolysis?
- Acute hemolytic transfusion reaction
- Febrile non-hemolytic transfusion reaction (FNHTR) (Correct answer)
- Allergic/urticarial reaction
- Transfusion-associated circulatory overload (TACO)
Correct answer: Febrile non-hemolytic transfusion reaction (FNHTR)
FNHTR is caused by recipient antibodies against donor leukocyte HLA antigens or by cytokines that accumulate in stored blood products, producing fever without red cell destruction.
Question 2: Transfusion-related acute lung injury (TRALI) is primarily caused by:
- ABO incompatibility between donor and recipient
- Donor antibodies activating recipient neutrophils in the lung vasculature (Correct answer)
- Bacterial contamination of the blood product
- Iron overload from chronic transfusion therapy
Correct answer: Donor antibodies activating recipient neutrophils in the lung vasculature
TRALI is predominantly caused by donor anti-HLA or anti-neutrophil antibodies that activate recipient neutrophils, triggering inflammatory lung injury within 6 hours of transfusion.
Question 3: An antibody identification panel in the blood bank is primarily used to:
- Confirm a patient's ABO and Rh blood type
- Identify the specificity of unexpected antibodies in patient serum (Correct answer)
- Screen donor blood for infectious disease markers
- Assess platelet function before transfusion
Correct answer: Identify the specificity of unexpected antibodies in patient serum
An antibody identification panel uses a set of reagent red cells with known antigen profiles to determine the specificity of an unexpected antibody detected in the patient's serum or plasma.
Question 4: The Kleihauer-Betke acid elution test is used to:
- Identify the Rh type of a newborn
- Quantify the volume of fetal red cells in maternal circulation (Correct answer)
- Detect irregular antibodies in prenatal patients
- Confirm ABO blood group in neonates
Correct answer: Quantify the volume of fetal red cells in maternal circulation
The Kleihauer-Betke test detects fetal hemoglobin (HbF) resistant to acid elution in maternal blood, allowing calculation of fetomaternal hemorrhage volume to determine Rh immune globulin dosing.
Question 5: An acute hemolytic transfusion reaction (AHTR) is most commonly caused by:
- Bacterial contamination of the blood unit
- ABO incompatibility due to clerical or identification error (Correct answer)
- Allergic response to donor plasma proteins
- Leukocyte cytokines in stored blood products
Correct answer: ABO incompatibility due to clerical or identification error
The majority of fatal AHTRs result from ABO incompatibility caused by clerical errors — such as transfusing the wrong blood to the wrong patient — leading to complement-mediated intravascular hemolysis.
Question 6: Warm autoimmune hemolytic anemia (WAIHA) is most commonly associated with which type of autoantibody?
- IgM cold-reactive agglutinin
- IgG pan-reactive antibody active at 37°C (Correct answer)
- IgA anti-D alloantibody
- IgM anti-I antibody
Correct answer: IgG pan-reactive antibody active at 37°C
WAIHA is characterized by IgG autoantibodies that react optimally at 37°C (body temperature) and are broadly reactive against common Rh antigens, producing a positive DAT (IgG).
Question 7: Enzyme treatment of reagent red cells (e.g., with papain or ficin) enhances detection of antibodies in which blood group systems?
- MNS and Duffy systems
- Rh and Kidd systems (Correct answer)
- ABO and Lewis systems
- Kell and Lutheran systems
Correct answer: Rh and Kidd systems
Proteolytic enzymes remove sialic acid from red cell surfaces, enhancing reactivity with Rh and Kidd antibodies while destroying M, N, S, Fy(a), and Fy(b) antigens.
MLS Blood Banking & Transfusion Medicine 2
Which transfusion reaction presents with fever, chills, and rigors within 1–6 hours post-transfusion without evidence of hemolysis?