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PA21.1-6 | Blood Groups & Transfusion Medicine — Graded Quiz
Graded
12 questions · Untimed · 2 attempts
Click any question card to reveal the correct answer.
A 35-year-old group O Rh-positive man receives an emergency transfusion of group A Rh-negative packed red cells due to a mix-up at the bedside. Within 30 minutes he develops severe loin pain, hypotension (BP 70/40 mmHg), fever (40°C), haemoglobinuria, and renal failure. Which sequence of events MOST accurately describes the pathophysiology of his reaction?
A
IgG anti-A in recipient serum crosses the placental barrier and destroys donor A cells in the spleen through extravascular haemolysis
B
Pre-formed IgM anti-A in recipient serum binds group A donor RBCs → IgM pentamer activates classical complement → MAC formation → intravascular haemolysis + haemoglobinaemia + renal failure
✓
C
Donor white cells in the packed red cell unit trigger a recipient anti-HLA antibody response causing acute lung injury
D
Recipient platelets aggregate on donor A antigen surface causing microangiopathic haemolysis and DIC
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A 26-year-old primigravida is Rh(D) negative. Her husband is Rh(D) positive (homozygous, DD). She declines anti-D immunoglobulin at 28 weeks, stating she 'doesn't believe in blood products on religious grounds.' She delivers an Rh(D)-positive baby at term. During the third stage of labour, a large feto-maternal haemorrhage is suspected. Which investigation best quantifies the volume of fetal red cells in the maternal circulation and determines the dose of anti-D required?
A
Kleihauer-Betke acid elution test — fetal HbF-containing cells resist acid elution and are visualised as pink cells on maternal blood film
✓
B
Direct antiglobulin test (DAT) on maternal blood — detects IgG coating on any fetal cells that entered maternal circulation
C
Indirect Coombs test (IAT) on maternal serum — detects anti-D alloantibody indicating sensitisation has already occurred
D
Ultrasound estimation of placental volume as a proxy for feto-maternal haemorrhage extent
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A 45-year-old man with decompensated cirrhosis requires surgery for a spontaneous bacterial peritonitis. Pre-operative work-up: PT 22 s (INR 1.9), aPTT 52 s, platelets 52,000/µL, fibrinogen 1.2 g/L. The anaesthetist requests FFP, platelets, and cryoprecipitate. Which blood component should be given FIRST to address the most critical haemostatic deficiency before surgical incision?
A
Platelet concentrate, as the platelet count of 52,000/µL is the most immediately life-threatening component of his coagulopathy for surgical haemostasis
B
Fresh frozen plasma, as it corrects the prolonged PT/aPTT from multiple factor deficiencies (factors V, VII, IX, X, and XI) and provides the largest volume of haemostatic factors per unit
C
Cryoprecipitate, as fibrinogen is the rate-limiting factor for clot formation at the surgical site, and fibrinogen 1.2 g/L is critically low, impairing fibrin polymer formation even with adequate factors and platelets
✓
D
Vitamin K IV, as the INR elevation in cirrhosis reflects vitamin K deficiency from impaired hepatic uptake
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A 23-year-old blood donor reports a recent trip to a malaria-endemic region (Assam) 6 weeks ago. He is asymptomatic. His blood is collected, processed, and all mandatory NACO screens are negative. He is cleared for release. Three weeks later, the recipient of his blood develops fever, rigors, and splenomegaly. The blood bank is notified of a suspected transfusion-transmitted malaria. Which feature of the parasitic infection MOST explains why current NACO mandatory screening failed to detect this unit?
A
Plasmodium falciparum undergoes antigenic variation that prevents antibody-based ELISA detection during the asymptomatic phase
B
The standard NACO mandatory screen panel does not include specific malaria antibody or antigen testing — malaria is detected only by clinical donor deferral policy (travel history exclusion), which failed here
✓
C
The donor was in the post-exposure window period for malaria serological testing at 6 weeks, when antibodies are not yet detectable
D
Plasmodium vivax can survive the storage conditions of packed red cells (2–6°C, 42 days) unlike other pathogens, evading standard inactivation protocols
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A 68-year-old man with congestive heart failure (ejection fraction 30%) and haemoglobin 7.2 g/dL receives 2 units of packed red cells. During the second unit, he develops progressive dyspnoea, orthopnoea, and hypertension (BP rises from 120/80 to 170/100 mmHg). Chest X-ray shows new bilateral infiltrates with enlarged cardiac silhouette. Oxygen saturation drops to 90%. Jugular venous pressure is elevated. There is no fever. Which diagnosis and MANAGEMENT is most appropriate?
A
TRALI — stop transfusion, give oxygen, avoid diuretics (may worsen hypotension), notify blood bank of implicated FFP-containing component
B
TACO (Transfusion-Associated Circulatory Overload) — stop transfusion, sit patient up, give IV furosemide, oxygen, and consider resuming transfusion at a slower rate only after resolution
✓
C
Acute haemolytic transfusion reaction — stop transfusion, send blood and urine to blood bank, start IV fluids and frusemide to protect kidneys
B
Febrile non-haemolytic transfusion reaction — give paracetamol, slow the transfusion rate, and monitor
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A 55-year-old woman with aplastic anaemia on immunosuppressive therapy receives a single-donor apheresis platelet transfusion from her HLA-matched brother. Three weeks later she develops fever, rash progressing to skin desquamation, profuse diarrhoea, and rising liver enzymes (ALT 380 U/L). Bone marrow biopsy shows near-total aplasia. Which transfusion complication explains this life-threatening clinical picture, and how could it have been PREVENTED?
A
Graft-versus-host disease from viable donor lymphocytes in the platelet component — prevented by gamma-irradiation (25–50 Gy) of the platelet unit before transfusion
✓
B
Platelet refractoriness from HLA alloimmunisation causing immune destruction of donor platelets with secondary cytokine storm
C
Bacterial sepsis from Klebsiella contamination of the platelet bag stored at room temperature — prevented by pathogen inactivation technology
D
Acute haemolytic reaction from ABO-incompatible plasma in the apheresis platelet unit — prevented by ABO-matched platelet selection
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A blood bank technician performs ABO grouping on a 70-year-old man with chronic lymphocytic leukaemia (CLL). Forward typing: Anti-A serum — no agglutination; Anti-B serum — no agglutination. Reverse typing: A₁ cells — no agglutination; B cells — no agglutination. The result is discrepant (expected group O would show Anti-A and Anti-B reactivity in reverse typing). Which explanation MOST likely accounts for this discrepancy?
A
CLL-related hypogammaglobulinaemia — severely reduced serum immunoglobulins lead to absent or weak naturally occurring anti-A and anti-B isoagglutinins in reverse typing
✓
B
Prozone effect from high-titer anti-A antibody — excess antibody prevents agglutination in both forward and reverse typing
C
Bombay phenotype (Oh) — absence of H antigen means no A or B antigen can be expressed, and reverse typing shows anti-A, anti-B, AND anti-H
D
Cold agglutinin disease from CLL-associated IgM causing spontaneous agglutination and false-negative reverse typing at room temperature
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A 40-year-old man with group B Rh-positive blood requires pre-operative crossmatch for elective knee replacement. The immediate-spin crossmatch is COMPATIBLE. The anti-human globulin (AHG) phase crossmatch is INCOMPATIBLE (agglutination after adding AHG). His antibody screen (indirect Coombs test, IAT) was positive. Which conclusion is MOST accurate about this crossmatch result?
A
The ABO/Rh typing was incorrect — the incompatibility indicates undiscovered ABO mismatch between donor and recipient
B
The recipient has an IgG alloantibody (likely against a non-ABO antigen such as Rh, Kell, Duffy, or Kidd) that reacts with the corresponding antigen on the donor's RBCs
✓
C
The donor unit is contaminated with bacteria, causing false-positive AHG reactivity through non-specific protein aggregation
D
The AHG serum is expired or faulty — the result should be repeated with a fresh AHG reagent before drawing clinical conclusions
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A 35-year-old woman with rare blood group (Rh-null phenotype) requires elective cardiac surgery. Compatible allogeneic blood cannot be located in any national blood bank. She prefers to avoid transfusion risk. Her haemoglobin is 12.6 g/dL and she is medically optimised. The surgical team plans to use intraoperative cell salvage. Which statement MOST accurately describes the rationale for choosing autologous transfusion in this patient?
A
Autologous blood eliminates risk of alloimmunisation and transfusion-transmitted infections since the patient receives her own blood
✓
B
Intraoperative cell salvage is contraindicated in cardiac surgery because heparinised blood from the bypass circuit cannot be processed by the cell saver
C
Autologous transfusion is safer than allogeneic because the patient's red cells survive longer in circulation after re-infusion
D
Cell salvage is the preferred method only for patients with religious objections to allogeneic blood; the indication in this case is religious, not medical
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A 22-year-old man with sickle cell disease has received 18 units of PRBC over his lifetime and is now found to have an alloantibody against Jkᵃ (Kidd system). His haemoglobin is 6.8 g/dL and he requires transfusion for a vaso-occlusive crisis. The blood bank reports it will take 48 hours to find a Jkᵃ-negative unit. Which transfusion strategy MOST appropriately balances immediate clinical need with alloimmunisation risk?
A
Transfuse any available compatible unit immediately — the risk of acute anaemia outweighs the risk of alloimmune haemolysis from Jkᵃ-incompatible blood
B
Wait 48 hours for phenotype-matched Jkᵃ-negative blood — Kidd antibodies (anti-Jkᵃ) are notorious for causing severe, potentially fatal delayed haemolytic transfusion reactions even when initially below detection levels
✓
C
Give albumin infusion as a plasma expander to maintain oncotic pressure while awaiting matched blood
D
Perform therapeutic plasmapheresis to remove anti-Jkᵃ antibodies before transfusion, then transfuse any unit
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During blood grouping in the blood bank, a technician uses a gel card (column agglutination technology) for ABO and Rh typing. The gel card for group O forward typing (no A or B antigens on RBCs) shows complete agglutination in the anti-D column (1+ strength), but no agglutination in the anti-D control column. Rh typing result is called as Rh-positive. However, the patient's prior type (6 months ago) was documented as Rh-negative. Which explanation is MOST likely for this discrepancy?
A
Patient has undergone spontaneous acquisition of D antigen from a recent infection, causing a new D-positive phenotype
B
The patient has Weak D (Du) — weak D antigen not detectable by routine saline antisera in past records, now detected by the sensitive gel card method which picks up weak D positivity
✓
C
The patient received an Rh-positive blood transfusion 6 months ago, and the transfused D-positive cells are still circulating and being typed as D-positive
D
Technical error in the current gel card test — a 1+ weak reaction should be interpreted as Rh-negative in the presence of a prior negative type
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A 48-year-old group A Rh-negative woman receives a blood transfusion. Her nurse checks the patient wristband against the blood product label at the bedside but does not check the date of birth — she confirms only the name (Mrs. Sharma), which matches both the wristband and the label. However, the unit was actually cross-matched for a different patient (also named Mrs. Sharma) on the same ward. The patient develops a severe acute haemolytic reaction 20 minutes later. Which root cause analysis finding MOST directly explains this preventable error?
A
The blood bank issued an ABO-incompatible unit because the forward typing for Mrs. Sharma 1 was performed incorrectly
B
Bedside pre-transfusion check failure — only one patient identifier (name) was confirmed instead of the mandatory two-identifier rule (name + date of birth/hospital number)
✓
C
The crossmatch was performed incorrectly — an incompatible unit passed the AHG phase test
D
The blood bag label was printed incorrectly by the blood bank information system, listing the wrong patient's name
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