Medical Laboratory Technician Exam FREE Medical Laboratory Technician Blood Banking and Transfusion Questions and Answers 2 — Questions and Answers
Question 1: A patient with blood type AB positive requires a platelet transfusion, but only type O platelets are available. What is the primary concern with this transfusion?
- Anti-A and anti-B antibodies in the donor plasma may cause hemolysis (Correct answer)
- The platelets will be immediately destroyed by the recipient's immune system
- Rh incompatibility will trigger an acute hemolytic reaction
- There is no concern because platelets do not carry ABO antigens
Correct answer: Anti-A and anti-B antibodies in the donor plasma may cause hemolysis
Type O platelet units contain donor plasma with anti-A and anti-B antibodies that can cause hemolysis of the recipient's red blood cells.
Question 2: During an antibody identification panel, a technologist notices that all panel cells positive for the Jka antigen are reactive. The autocontrol is negative. Which additional test would best confirm anti-Jka?
- Enzyme-treated panel cells (Correct answer)
- Ficin-treated panel cells to destroy Jka antigen
- Cord blood cells
- Neutralization with soluble Jka substance
Correct answer: Enzyme-treated panel cells
Kidd antibodies are enhanced by enzyme treatment, so enzyme-treated panel cells would strengthen the reactions and help confirm anti-Jka.
Question 3: A crossmatch is incompatible at the antihuman globulin (AHG) phase. The antibody screen is negative. What is the most likely cause?
- An antibody directed against a low-frequency antigen on the donor cells (Correct answer)
- ABO incompatibility between donor and recipient
- A cold autoantibody interfering at 37°C
- Contamination of the reagent red cells
Correct answer: An antibody directed against a low-frequency antigen on the donor cells
A negative antibody screen with an incompatible crossmatch at AHG suggests an antibody to a low-frequency antigen present on the donor cells but absent from screening cells.
Question 4: Which of the following is the most appropriate product for a neonate requiring an exchange transfusion for hemolytic disease of the fetus and newborn (HDFN) caused by anti-D?
- Group O, Rh-negative red blood cells resuspended in AB plasma (Correct answer)
- Group O, Rh-positive red blood cells in saline
- Mother's own red blood cells, washed
- Group-specific Rh-negative whole blood
Correct answer: Group O, Rh-negative red blood cells resuspended in AB plasma
Group O Rh-negative RBCs avoid ABO and Rh incompatibility, and AB plasma lacks anti-A and anti-B antibodies that could harm the neonate's cells.
Question 5: A blood bank technologist performs a DAT on a post-transfusion sample and obtains a mixed-field reaction. What does this finding most likely indicate?
- Circulating transfused donor cells are being coated with recipient antibody in vivo (Correct answer)
- The patient has a cold autoantibody
- The polyspecific AHG reagent is contaminated
- The patient has a positive DAT due to drug-induced antibody
Correct answer: Circulating transfused donor cells are being coated with recipient antibody in vivo
A mixed-field DAT after transfusion indicates that some cells (transfused donor cells) are coated with antibody while the patient's own cells remain uncoated.
Question 6: Which storage lesion change is most significant in red blood cells stored beyond 35 days in CPDA-1?
- Decreased 2,3-DPG levels causing increased oxygen affinity (Correct answer)
- Increased ATP levels
- Decreased potassium concentration in the supernatant
- Improved red cell deformability
Correct answer: Decreased 2,3-DPG levels causing increased oxygen affinity
Stored red blood cells progressively lose 2,3-DPG, which increases hemoglobin's oxygen affinity and reduces oxygen delivery to tissues.
