Component therapy

11 ASCP MLS practice questions on Component therapy, part of Blood Banking. The first 11 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

1. Question 1 · Hard

   A bleeding patient with anti-K needs red cells, plasma and platelets. Which components must be K-negative?

   1. AAll three components
   2. BRed cells only
   3. CPlasma only
   4. DRed cells and platelets

   Show answerHide answer

   Answer: B · Red cells only

   The patient's anti-K would destroy K-positive red cells, so red cell units must be K-negative and crossmatch-compatible. Plasma and platelets contain too few red cells to cause a reaction, so they need no antigen selection. Plasma and platelets are chosen by ABO compatibility instead. This keeps antigen-negative searches limited to the component that matters.

   • A: Plasma and platelets contain too few red cells to need K-negative selection.
   • C: Plasma has no red cells to carry K antigen.
   • D: Platelets do not need antigen-negative selection for red cell antibodies.

2. Question 2 · Medium

   A preterm neonate needs a top-up red cell transfusion. The usual dose is about:

   1. A40 mL/kg
   2. B10 to 15 mL/kg
   3. C1 to 2 mL/kg
   4. DOne whole adult unit

   Show answerHide answer

   Answer: B · 10 to 15 mL/kg

   Neonatal top-up transfusions are usually 10 to 15 mL/kg, given over a few hours. This raises the hemoglobin by about 2 to 3 g/dL. Units are often divided into aliquots from one donor to limit donor exposures. Aliquots are usually irradiated and CMV-safe for preterm infants.

   • A: 40 mL/kg is close to half a neonate's blood volume and risks overload.
   • C: 1 to 2 mL/kg is too small to raise the hemoglobin usefully.
   • D: A whole adult unit is far too large for a neonate.

3. Question 3 · Medium

   A group O patient needs platelets, but only group A platelets are available. Can they be given?

   1. AOnly after washing to remove the plasma
   2. BNo; platelets must always be ABO-identical
   3. COnly after a full AHG crossmatch with the unit
   4. DYes; ABO-incompatible platelets are acceptable

   Show answerHide answer

   Answer: D · Yes; ABO-incompatible platelets are acceptable

   Platelets carry weak A and B antigens, so ABO-incompatible platelets give a somewhat lower increment but are still effective. When identical units are short, giving them is standard practice. Platelets do not need a crossmatch, because they contain very few red cells. The donor plasma's ABO antibodies are the other consideration.

   • A: Washing is not needed and damages platelets.
   • B: ABO-identical platelets are preferred but not required.
   • C: Platelets are not crossmatched.

4. Question 4 · Hard

   A group A patient receives a group O apheresis platelet unit. What is the main risk?

   1. AA lower platelet increment
   2. BA febrile reaction from donor white cells
   3. CAlloimmunization to Rh antigens
   4. DHemolysis from anti-A in the donor plasma

   Show answerHide answer

   Answer: D · Hemolysis from anti-A in the donor plasma

   Group O apheresis platelets carry about 200 to 300 mL of plasma, and some donors have high-titer anti-A. This plasma can hemolyze a group A recipient's red cells, especially in children. Many centers limit this risk by titer screening, volume reduction or platelet additive solution. A lower increment comes from the opposite mismatch, when the platelets carry an antigen the recipient's plasma reacts with.

   • A: A lower increment comes from the platelets' own A or B antigens meeting the recipient's antibody.
   • B: Febrile reactions are not the main ABO-related risk.
   • C: Apheresis platelets contain very few red cells, so Rh alloimmunization is not the main concern.

5. Question 5 · Hard

   A patient with IgA deficiency has no anti-IgA and has never reacted to transfusion. Which plasma should be given?

   1. APlasma from IgA-deficient donors only
   2. BSolvent/detergent plasma only
   3. CStandard plasma
   4. DWashed plasma

   Show answerHide answer

   Answer: C · Standard plasma

   Most IgA-deficient people never make anti-IgA or react to blood. IgA-deficient products are needed only for patients with anti-IgA and a history of anaphylaxis. Standard plasma is therefore appropriate here. Plasma cannot be washed, because it is the plasma itself.

   • A: IgA-deficient donor plasma is reserved for patients with anti-IgA and a reaction history.
   • B: Solvent/detergent plasma is not required for IgA deficiency without anti-IgA.
   • D: Plasma cannot be washed; washing removes plasma.

6. Question 6 · Medium

   A patient with chronic kidney failure has bleeding from a biopsy site. The platelet count is normal. Which treatment is first-line?

   1. AFresh frozen plasma
   2. BDesmopressin (DDAVP)
   3. CWhole blood
   4. DProphylactic platelets

   Answer and explanation in LearnFree account

7. Question 7 · Hard

   A patient with severe hemophilia A has developed a high-titer factor VIII inhibitor and is bleeding. Which product is most appropriate?

   1. AA bypassing agent, such as recombinant factor VIIa
   2. BFactor VIII concentrate at the usual weight-based dose
   3. CCryoprecipitate
   4. DPlatelets

   Answer and explanation in LearnFree account

8. Question 8 · Easy

   The usual therapeutic dose of plasma for an adult with clotting factor deficiency is about:

   1. A40 to 50 mL/kg
   2. B10 to 20 mL/kg
   3. C100 mL/kg
   4. D2 to 5 mL/kg

   Answer and explanation in LearnFree account

9. Question 9 · Hard

   An adult with immune thrombocytopenia (ITP) has a platelet count of 8 × 10^9/L and only a few petechiae. What is the usual management?

   1. AProphylactic platelets to keep the count above 10
   2. BPlasma to supply clotting factors
   3. CCorticosteroids or IVIG; no routine platelets
   4. DCryoprecipitate to support clotting

   Answer and explanation in LearnFree account

10. Question 10 · Medium

    A bleeding patient with DIC has platelets 30 × 10^9/L, fibrinogen 90 mg/dL (0.9 g/L) and a prolonged PT. Which treatment is most appropriate?

    1. ATranexamic acid alone, to stop fibrinolysis
    2. BPlatelets, cryoprecipitate and plasma
    3. CRed cells alone, to restore oxygen delivery
    4. DHeparin infusion alone, no components

    Answer and explanation in LearnFree account

11. Question 11 · Hard

    A 68-year-old man with chronic lymphocytic leukemia was treated with fludarabine-based chemotherapy last year. He is admitted with pneumonia and gum bleeding. Results: hemoglobin 6.8 g/dL (68 g/L), platelets 9 x 10^3/µL (9 x 10^9/L), INR 2.0, fibrinogen 210 mg/dL (2.1 g/L). The physician orders 1 unit of leukoreduced red cells, 1 leukoreduced apheresis platelet unit and 2 units of thawed plasma. No pathogen-reduced platelets are in stock. Which of these components must be irradiated before issue?

    1. ARed cells, platelets and plasma
    2. BRed cells and platelets only
    3. COnly the platelet component
    4. DNone, since all are leukoreduced

    Answer and explanation in LearnFree account