ABPath - American Board of Pathology Blood Banking and Transfusion Questions and Answers 1 — Questions and Answers
Question 1: A 68-year-old male with a history of myelodysplastic syndrome receives a transfusion of 2 units of packed red blood cells. Five days later, he presents with a low-grade fever, mild jaundice, and a greater than expected drop in his hemoglobin level. A direct antiglobulin test (DAT) is now positive. Which of the following is the most likely cause of this presentation?
- Acute hemolytic transfusion reaction
- Delayed hemolytic transfusion reaction (Correct answer)
- Transfusion-associated graft-versus-host disease (TA-GVHD)
- Febrile non-hemolytic transfusion reaction
Correct answer: Delayed hemolytic transfusion reaction
The patient's presentation of symptoms such as fever and jaundice several days after a transfusion, along with a positive DAT and unexpected anemia, is characteristic of a delayed hemolytic transfusion reaction (DHTR). [8, 15] This reaction occurs when a patient has been previously sensitized to a red blood cell antigen and has an anamnestic antibody response upon re-exposure through transfusion. [26] Acute reactions occur within 24 hours, TA-GVHD has different primary symptoms, and febrile reactions typically do not involve hemolysis or a positive DAT.
Question 2: A blood bank technologist is resolving an ABO discrepancy. The forward typing shows A positive, while the reverse typing is consistent with group O (anti-A and anti-B are reactive). The patient is a 75-year-old male with multiple myeloma. What is the most likely cause of this discrepancy?
- A weak subgroup of A
- Recent transfusion with group O red cells
- Cold agglutinins
- Rouleaux formation (Correct answer)
Correct answer: Rouleaux formation
The discrepancy described (forward type A, reverse type O) is a classic example of a Group III ABO discrepancy. [2] In patients with conditions causing hyperproteinemia, such as multiple myeloma, red blood cells can non-specifically aggregate in a 'stack of coins' appearance known as rouleaux formation. [14] This can cause false agglutination in the forward typing. Saline replacement or dilution techniques can typically resolve this type of discrepancy. [14]
Question 3: Which of the following is the primary reason for irradiating cellular blood components?
- To prevent bacterial contamination
- To inactivate viruses such as CMV and HIV
- To prevent transfusion-associated graft-versus-host disease (TA-GVHD) (Correct answer)
- To reduce the risk of febrile non-hemolytic transfusion reactions
Correct answer: To prevent transfusion-associated graft-versus-host disease (TA-GVHD)
The sole purpose of irradiating cellular blood products is to inactivate donor T-lymphocytes, thereby preventing their proliferation and engraftment in a susceptible recipient. [19, 36, 38] This action prevents transfusion-associated graft-versus-host disease (TA-GVHD), a rare but highly fatal complication of transfusion. [36, 39] Irradiation does not eliminate bacteria or viruses.
Question 4: A patient with disseminated intravascular coagulation (DIC) and significant hypofibrinogenemia requires factor replacement. Which blood component is the most concentrated source of fibrinogen?
- Fresh Frozen Plasma (FFP)
- Cryoprecipitate (Correct answer)
- Platelets
- Packed Red Blood Cells (PRBCs)
Correct answer: Cryoprecipitate
Cryoprecipitate is a plasma-derived product that is prepared by thawing Fresh Frozen Plasma and collecting the cold-insoluble precipitate. [5, 13] This process concentrates several clotting factors, most notably fibrinogen, as well as Factor VIII, Factor XIII, and von Willebrand factor. [10, 37] It is the most concentrated source of fibrinogen available for transfusion. [10]
Question 5: A patient develops acute respiratory distress, hypoxemia, and bilateral pulmonary infiltrates on chest X-ray within 2 hours of receiving a platelet transfusion. There are no signs of circulatory overload. Which of the following is the most likely diagnosis?
- Anaphylactic transfusion reaction
- Transfusion-Associated Circulatory Overload (TACO)
- Transfusion-Related Acute Lung Injury (TRALI) (Correct answer)
- Septic transfusion reaction
Correct answer: Transfusion-Related Acute Lung Injury (TRALI)
The clinical presentation of acute respiratory distress, non-cardiogenic pulmonary edema, and hypoxemia occurring within 6 hours of a transfusion is the classic definition of Transfusion-Related Acute Lung Injury (TRALI). [4, 18, 35] It is a leading cause of transfusion-related mortality. [4] The absence of signs of heart failure or volume overload helps distinguish it from TACO. [28]
Question 6: Which of the following infectious agents is NOT universally tested for on all allogeneic blood donations in the United States?
- Human Immunodeficiency Virus (HIV)
- Hepatitis C Virus (HCV)
- Cytomegalovirus (CMV) (Correct answer)
- Hepatitis B Virus (HBV)
Correct answer: Cytomegalovirus (CMV)
While all blood donations in the U.S. are tested for a panel of infectious agents including HIV, HCV, HBV, and others, Cytomegalovirus (CMV) testing is not performed on every unit. [9, 12, 23] CMV testing is typically performed on a subset of donations to provide CMV-seronegative products for specific at-risk patient populations, such as premature infants and transplant recipients.
ABPath - American Board of Pathology Blood Banking and Transfusion Questions and Answers 1
A 68-year-old male with a history of myelodysplastic syndrome receives a transfusion of 2 units of packed red blood cells.
Five days later, he presents with a low-grade fever, mild jaundice, and a greater than expected drop in his hemoglobin level.
A direct antiglobulin test (DAT) is now positive.
Which of the following is the most likely cause of this presentation?