Free Medical Laboratory Technician Blood Banking and Transfusion Questions and Answers — Questions and Answers
Question 1: A patient experiences fever, chills, and flank pain 15 minutes after the start of a red blood cell transfusion. The transfusion is stopped immediately. What is the most likely cause of this transfusion reaction?
- Febrile non-hemolytic reaction
- Allergic reaction
- Acute hemolytic transfusion reaction (Correct answer)
- Transfusion-associated circulatory overload (TACO)
Correct answer: Acute hemolytic transfusion reaction
The classic symptoms of fever, chills, and flank pain are strongly indicative of an acute hemolytic transfusion reaction (AHTR), which is a medical emergency. This type of reaction is most often caused by an ABO incompatibility, leading to rapid intravascular destruction of the transfused red cells. While a febrile non-hemolytic reaction involves fever and chills, flank pain is not a typical symptom. Allergic reactions usually present with urticaria and itching, and TACO is characterized by respiratory distress due to fluid overload.
Question 2: Which of the following blood components must be prepared from a whole blood donation within 8 hours of collection to maintain optimal levels of all coagulation factors?
- Packed Red Blood Cells (PRBCs)
- Fresh Frozen Plasma (FFP) (Correct answer)
- Cryoprecipitate
- Platelets
Correct answer: Fresh Frozen Plasma (FFP)
Fresh Frozen Plasma (FFP) must be separated from whole blood and frozen, typically within 8 hours of collection, to preserve the labile coagulation factors, particularly Factor V and Factor VIII. Processing after this timeframe results in a product called Plasma Frozen within 24 hours (PF24), which has reduced levels of these factors. PRBCs, platelets, and cryoprecipitate have different processing timeframes and requirements.
Question 3: An ABO discrepancy is observed in a 75-year-old patient. The forward typing shows A positive, while the reverse typing shows no reaction with A1 cells or B cells. What is the most likely cause of this discrepancy?
- Presence of a cold autoantibody
- Subgroup of A
- Recent transfusion with group O blood
- Weak or missing antibodies (Correct answer)
Correct answer: Weak or missing antibodies
The discrepancy shows a lack of expected anti-B antibodies in the reverse typing. In elderly patients, antibody production can decrease, leading to weak or missing isoagglutinins. A subgroup of A would likely show a weaker reaction with anti-A, and potentially an anti-A1. A cold autoantibody would typically cause extra agglutination. A recent transfusion with group O blood would not eliminate the patient's native anti-B.
Question 4: A Direct Antiglobulin Test (DAT) is performed to detect which of the following?
- Unexpected antibodies in the patient's serum
- Antigens on the patient's red blood cells
- In-vivo sensitization of red blood cells with antibodies or complement (Correct answer)
- In-vitro sensitization of reagent red blood cells
Correct answer: In-vivo sensitization of red blood cells with antibodies or complement
The Direct Antiglobulin Test (DAT), or Direct Coombs test, is used to detect red blood cells that have been sensitized with antibodies or complement in the body (in-vivo). This is a key test in the investigation of hemolytic transfusion reactions, hemolytic disease of the fetus and newborn (HDFN), and autoimmune hemolytic anemias. The Indirect Antiglobulin Test (IAT) is used to detect unexpected antibodies in patient serum (in-vitro sensitization).
Question 5: To prevent alloimmunization to leukocyte antigens in chronically transfused patients, which blood product modification is most effective?
- Irradiation
- Washing
- Volume reduction
- Leukoreduction (Correct answer)
Correct answer: Leukoreduction
Leukoreduction is the process of removing white blood cells (leukocytes) from a blood component. This is the most effective method for reducing the risk of febrile non-hemolytic transfusion reactions and alloimmunization to HLA antigens, which are present on leukocytes. Irradiation prevents transfusion-associated graft-versus-host disease, while washing removes plasma proteins to prevent allergic reactions.
Question 6: A trauma patient with blood type O negative arrives at the emergency department. The blood bank has a limited supply of O negative red blood cells. Which of the following blood types can be safely transfused to this patient as an alternative if O negative is unavailable?
- O positive
- A negative
- B negative
- No other type is safe (Correct answer)
Correct answer: No other type is safe
For an O negative patient, no other blood type is safely compatible for red cell transfusion. Group O patients have anti-A and anti-B antibodies, so they cannot receive A, B, or AB red cells. As they are Rh negative, transfusing Rh positive blood (like O positive) could cause them to develop anti-D antibodies, which can lead to future transfusion complications. In a dire emergency, O positive might be considered for a male or female past childbearing age, but it is not considered a routinely safe alternative.
Free Medical Laboratory Technician Blood Banking and Transfusion Questions and Answers
A patient experiences fever, chills, and flank pain 15 minutes after the start of a red blood cell transfusion.
The transfusion is stopped immediately.
What is the most likely cause of this transfusion reaction?