ABPath - American Board of Pathology Blood Banking and Transfusion 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?

Accepted Answer

Delayed hemolytic transfusion reaction

Answer

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?

Accepted Answer

Rouleaux formation

Answer

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?

Accepted Answer

To prevent transfusion-associated graft-versus-host disease (TA-GVHD)

Answer

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?

Accepted Answer

Cryoprecipitate

Answer

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?

Accepted Answer

Transfusion-Related Acute Lung Injury (TRALI)

Answer

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]

American Board of Pathology (ABPath) Practice Test

American Board of Pathology (ABPath) Practice Test

ABPath - American Board of Pathology Blood Banking and Transfusion Questions and Answers