MLT GlobeBlood Banking: Transfusion reactions – page 2
51 Blood Banking MCQs on Transfusion reactions with answers and explanations.
During rapid transfusion of many plasma-rich units, a patient develops perioral tingling and prolonged QT interval. The most likely cause is:
Citrate in the anticoagulant binds ionized calcium, especially when liver clearance is poor. Hypocalcemia causes paresthesia and cardiac changes; calcium is given as treatment.
A transfusion reaction is reported. Which three checks form the initial laboratory investigation?
The immediate workup includes a clerical check of labels and records, inspection of post-transfusion plasma for free hemoglobin, and a DAT. Further tests are done only if these suggest hemolysis.
Which laboratory pattern best supports intravascular hemolysis after transfusion?
Free hemoglobin binds haptoglobin, which falls quickly; LDH rises from lysed cells and excess hemoglobin appears in urine. Haptoglobin is not increased during hemolysis.
Which finding meets the usual definition of a febrile non-hemolytic transfusion reaction?
FNHTR is a temperature of 38 °C or more with a rise of 1 °C or more during or soon after transfusion. It is a diagnosis of exclusion after hemolysis and sepsis are ruled out.
Febrile non-hemolytic reactions to platelet transfusions are often caused by:
White cells in the bag release cytokines such as IL-1, IL-6 and TNF during room-temperature storage. Prestorage leukocyte reduction lowers these reactions.
During red cell transfusion, a patient develops a few itchy hives only. Vital signs are normal. What is appropriate?
Mild urticaria without other signs is the only reaction in which the same unit may be restarted after treatment. A hemolytic workup is not needed for isolated hives.
An 80-year-old with heart failure becomes breathless during her second red cell unit. BP 180/100 mmHg, distended neck veins, raised NT-proBNP. The most likely reaction is:
Hypertension, raised venous pressure and a high BNP point to volume overload. TRALI typically causes hypotension and a normal BNP, and it is not related to fluid volume.
What is the main mechanism of most TRALI cases?
Donor antibodies to HLA or neutrophil antigens activate recipient neutrophils in lung capillaries, causing leaky vessels. This is why plasma from men or never-pregnant women is preferred.
Why can Yersinia enterocolitica contaminate red cell units and cause septic reactions?
Yersinia is cold-tolerant and iron-loving, so it multiplies in refrigerated red cells and releases endotoxin. Most other bacteria grow better in platelets at room temperature.
A patient develops high fever, rigors and shock soon after a platelet transfusion. Septic reaction is suspected. Which test is most important?
Suspected bacterial contamination is investigated by Gram stain and culture of the returned bag and blood cultures from the patient. Hemolysis tests are also done but do not identify sepsis.
Ten days after transfusion, an immunocompromised patient has fever, rash, diarrhea, abnormal liver tests and pancytopenia. Which is most likely?
TA-GVHD usually appears 8–10 days after transfusion with rash, diarrhea, liver damage and marrow aplasia. It is fatal in over 90% of cases, so prevention by irradiation is essential.
Which patient does NOT require irradiated cellular components?
Irradiation is indicated for intrauterine transfusion, Hodgkin lymphoma, purine analogue therapy and other high-risk settings. Routine surgical patients with normal immunity do not need it.
A multiparous woman has a platelet count of 5 × 10^9/L with bleeding 8 days after a red cell transfusion. Which antibody is most likely responsible?
Post-transfusion purpura occurs 5–10 days after transfusion, mostly in HPA-1a-negative women sensitized by pregnancy. Their own platelets are destroyed too; IVIG is the treatment.
A patient taking an ACE inhibitor has a sudden fall in blood pressure early in a platelet transfusion, without fever or urticaria. Which mediator is most likely involved?
ACE breaks down bradykinin. In patients on ACE inhibitors, bradykinin generated during transfusion or filtration accumulates and causes hypotension, which recovers quickly when transfusion stops.
Hemoglobinuria follows a transfusion. Clerical check is correct, ABO types are compatible and the DAT is negative. The unit was warmed in a water bath at 50 °C. The cause is:
Heating red cells above the safe limit damages them and releases hemoglobin without any antibody. Blood must be warmed only with an approved, temperature-controlled device.
Why is hyperkalemia a concern when older irradiated red cells are used for neonatal exchange or large-volume transfusion?
Irradiation damages the red cell membrane and speeds potassium leakage during storage. For large neonatal transfusions, fresh or washed irradiated red cells are preferred.
Respiratory distress develops within 24 hours of transfusion. It does not meet the criteria for TRALI, TACO or allergic reaction. This is classified as:
TAD is respiratory distress within 24 hours that cannot be explained by TRALI, TACO, allergy or the patient's condition. It is a diagnosis of exclusion in hemovigilance definitions.
A patient has post-transfusion purpura with severe bleeding. Which treatment is first-line?
IVIG is first-line and usually raises the platelet count within days. Random platelets are usually destroyed quickly and give little benefit.
Which organism group most often contaminates platelet units and causes septic transfusion reactions?
Platelets are stored at room temperature, so skin flora such as Staphylococcus species (and other Gram-positive cocci) grow well. Yersinia is typically linked to refrigerated red cells.
A suspected acute hemolytic reaction is investigated. The group O patient's post-transfusion sample shows mixed-field agglutination with anti-A. This suggests:
A mixed-field reaction with anti-A means two red cell populations: the patient's O cells and transfused A cells. This supports an ABO-incompatible transfusion, often due to misidentification.