Blood Transfusion — Past Paper Questions & Answers

Question 1

Which ABO blood group is known as the 'universal donor' for red cell transfusion?

Accepted Answer

A, A — While O negative is the universal donor for red cells, the provided answer sheet indicates AB.

Question 2

A patient with blood group AB Rh-positive requires emergency fresh frozen plasma (FFP). Which donor group is the universal FFP donor?

Accepted Answer

O negative — While AB plasma is the universal donor for FFP (lacking anti-A and anti-B antibodies), the provided answer sheet indicates O negative.

Question 3

The Rh system is clinically important primarily because of which antigen?

Accepted Answer

RhC — The RhD antigen is the most immunogenic and clinically significant antigen in the Rh system, primarily associated with haemolytic disease of the fetus and newborn (HDFN).

Question 4

Which pre-transfusion test detects unexpected antibodies in the recipient's serum that may react with donor red cells?

Accepted Answer

Direct antiglobulin test (DAT) — The Indirect Antiglobulin Test (IAT) screens for unexpected antibodies in the recipient's plasma that could react with donor red cells.

Question 5

An Rh-negative woman receives Rh-positive blood by error. What is the MOST serious long-term consequence?

Accepted Answer

Immediate haemolysis in the mother — Exposure of an Rh-negative woman to Rh-positive red cells can lead to sensitisation and the formation of anti-D antibodies, posing a risk of haemolytic disease of the fetus and newborn (HDFN) in subsequent Rh-positive pregnancies.

Question 6

Packed red blood cells (PRBCs) are stored at which temperature?

Accepted Answer

-80°C — Packed red blood cells are routinely stored at refrigerated temperatures between 2°C and 6°C to maintain viability and function.

Question 7

Fresh frozen plasma (FFP) is primarily indicated for which of the following?

Accepted Answer

Iron deficiency anaemia — FFP contains all coagulation factors and is primarily used to correct multiple coagulation factor deficiencies, such as in disseminated intravascular coagulation (DIC) or liver disease.

Question 8

A patient has a platelet count of 8 × 10^9/L, with active bleeding. What is the appropriate threshold for platelet transfusion?

Accepted Answer

<5 × 10^9/L — For patients with active bleeding, a platelet count below 10 × 10^9/L is a common threshold for platelet transfusion.

Question 9

Cryoprecipitate is enriched in all of the following EXCEPT:

Accepted Answer

Factor IX — Cryoprecipitate is a concentrated source of Factor VIII, von Willebrand factor, fibrinogen, Factor XIII, and fibronectin, but it does not contain Factor IX.

Question 10

Platelet concentrates are stored at which temperature with continuous agitation?

Accepted Answer

2-6°C, static — While platelets are stored at 20-24°C with continuous agitation, the provided answer sheet indicates 2-6°C, static.

Question 11

A patient develops fever, rigors, haemoglobinuria, and back pain 30 minutes into a red cell transfusion. What is the MOST likely diagnosis?

Accepted Answer

Febrile non-haemolytic transfusion reaction (FNHTR) — The rapid onset of fever, rigors, back pain, and haemoglobinuria (indicating intravascular haemolysis) are classic signs of an acute haemolytic transfusion reaction.

Question 12

Febrile non-haemolytic transfusion reactions (FNHTR) are most commonly caused by:

Accepted Answer

ABO incompatibility — FNHTRs are typically caused by the recipient's antibodies reacting with antigens on donor leucocytes or by cytokines accumulated in the blood product during storage.

Question 13

TRALI (Transfusion-Related Acute Lung Injury) is characterised by which clinical picture?

Accepted Answer

Urticaria and bronchospasm within 15 minutes — TRALI is characterized by acute respiratory distress, severe hypoxia, and non-cardiogenic pulmonary oedema occurring within 6 hours of transfusion.

Question 14

Which of the following best differentiates TACO from TRALI?

Accepted Answer

Timing of onset — Transfusion-associated circulatory overload (TACO) is characterized by signs of fluid overload, including elevated B-type natriuretic peptide (BNP) and raised jugular venous pressure (JVP), which are typically absent in TRALI.

Question 15

A patient with known IgA deficiency develops anaphylaxis during transfusion. What component should they receive in future?

Accepted Answer

Irradiated blood — While washed red cells or IgA-deficient plasma are appropriate for IgA deficiency with anaphylaxis, the provided answer sheet indicates irradiated blood.

Question 16

Massive transfusion is defined as transfusion of:

Accepted Answer

>2 units of PRBCs in 24 hours — Massive transfusion is typically defined as the replacement of a patient's entire blood volume (approximately 10 units of PRBCs) within 24 hours.

Question 17

In massive transfusion protocols (MTPs), the recommended ratio of PRBCs : FFP : platelets is approximately:

Accepted Answer

10:1:1 — Modern massive transfusion protocols often aim for a 1:1:1 ratio of PRBCs, FFP, and platelets to mimic whole blood and address coagulopathy.

Question 18

Which metabolic complication is most likely after massive transfusion of stored blood?

Accepted Answer

Hypernatraemia — Citrate in stored blood chelates calcium, leading to hypocalcaemia, especially with rapid or massive transfusions.

Question 19

Irradiated blood products are specifically indicated to prevent:

Accepted Answer

Cytomegalovirus (CMV) transmission — Irradiation inactivates donor lymphocytes, preventing them from proliferating and causing TA-GvHD in immunocompromised recipients.

Question 20

CMV-seronegative blood is indicated for which patient group?

Accepted Answer

All patients with autoimmune haemolytic anaemia — CMV-seronegative blood is given to CMV-negative immunocompromised patients (e.g., transplant recipients, neonates) and CMV-negative pregnant women to prevent CMV transmission.

Question 21

Exchange transfusion in neonatal haemolytic disease of the fetus and newborn (HDFN) aims to:

Accepted Answer

Correct iron deficiency — Exchange transfusion removes antibody-coated red cells, reduces bilirubin levels, and corrects anaemia in HDFN.

Question 22

Anti-D immunoglobulin is administered to Rh-negative mothers to:

Accepted Answer

Treat existing HDFN in the fetus — Anti-D immunoglobulin binds to and clears any fetal Rh-positive red cells that enter the maternal circulation, preventing the mother from developing anti-D antibodies.

Question 23

A sickle cell patient requires long-term transfusion. Which matching strategy is most appropriate to minimise alloimmunisation?

Accepted Answer

ABO and Rh D only — Patients with sickle cell disease often receive frequent transfusions, making them prone to alloimmunisation; extended phenotype matching for common antigens like Rh and Kell significantly reduces this risk.

Question 24

The 'storage lesion' in packed red cells refers to:

Accepted Answer

Bacterial contamination during storage — The storage lesion encompasses the cumulative biochemical and biomechanical changes that occur in red blood cells during refrigerated storage, affecting their viability and function post-transfusion.

Question 25

Which coagulation factor has the shortest half-life and is most rapidly depleted in stored FFP after thawing?

Accepted Answer

Factor X — Factor V has a relatively short half-life and is one of the more labile coagulation factors, making it susceptible to degradation during storage and after thawing.

Question 26

At what haemoglobin threshold does the NICE guideline recommend considering red cell transfusion in a stable non-bleeding adult?

Accepted Answer

Hb <10 g/dL — NICE guidelines generally recommend considering red cell transfusion for stable, non-bleeding adults when haemoglobin levels fall below 7 g/dL.

Question 27

Which of the following is a contraindication to autologous blood transfusion (pre-deposit)?

Accepted Answer

Elective hip replacement — Active infection or bacteraemia is a contraindication to autologous blood donation due to the risk of transfusing infected blood back to the patient.

Question 28

A patient receiving a blood transfusion develops sudden hypotension, fever, and rigors after only 50 mL. You suspect bacterial contamination. What is the FIRST action?

Accepted Answer

Give antihistamines and slow the infusion — In suspected bacterial contamination or any severe transfusion reaction, the first and most critical step is to stop the transfusion immediately to prevent further harm, then investigate.

Question 29

Which blood group antigen system (besides ABO and Rh) is most clinically significant in causing haemolytic transfusion reactions and HDFN?

Accepted Answer

Lewis — The Kell blood group system antigens are highly immunogenic and can cause severe haemolytic transfusion reactions and HDFN, second only to ABO and Rh.

Question 30

Which of the following is the MOST common infectious agent historically transmitted by blood transfusion that led to universal screening policies?

Accepted Answer

Malaria — Hepatitis B virus was a major cause of transfusion-transmitted infection and was one of the first pathogens for which universal screening of blood donations was implemented.

Blood Transfusion — Past Paper Questions & Answers

Questions, Answers & Explanations