Eight days after a red cell transfusion, a patient with sickle cell anemia (Hb SS) has pain, fever and dark urine. Which result best shows that the transfused red cells are being destroyed?

Hb A has fallen from 40% to 10%

LD has risen to twice the upper limit

Total bilirubin is 70 µmol/L (4.1 mg/dL)

A 19-year-old with sickle cell disease types e-positive. After transfusion with e-positive red cells, she develops anti-e, while her DAT and autocontrol stay negative. What is the most likely explanation?

A partial e antigen from a variant RHCE allele

Passive anti-e from a recent plasma transfusion

A false e-positive type caused by a positive DAT

A warm autoantibody with e-like specificity

Which test best shows iron loading of the heart in a patient with transfusion-dependent thalassemia?

Liver biopsy iron concentration

Transfusion in thalassemia and sickle cell disease

9 DOH Abu Dhabi (HAAD) lab licensing practice questions on Transfusion in thalassemia and sickle cell disease, part of Blood Banking. The first 9 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Hard
Eight days after a red cell transfusion, a patient with sickle cell anemia (Hb SS) has pain, fever and dark urine. Which result best shows that the transfused red cells are being destroyed?
1. ALD has risen to twice the upper limit
2. BHb A has fallen from 40% to 10%
3. CTotal bilirubin is 70 µmol/L (4.1 mg/dL)
4. DReticulocytes are 12%
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Answer: B · Hb A has fallen from 40% to 10%
A patient with Hb SS makes no Hb A, so the Hb A percentage measured by HPLC directly tracks the donor cells still in the circulation. A rapid fall in Hb A within days shows that the transfused cells are being destroyed, as in a delayed hemolytic transfusion reaction. Raised LD, bilirubin and reticulocytes are also seen in a sickle cell crisis, so they cannot separate the two. The work-up then includes a DAT, antibody screen and eluate, although an antibody is not always found.
- A: LD rises in a sickle crisis and in hemolysis of the patient's own cells.
- C: Bilirubin is often raised in sickle cell anemia and during a crisis.
- D: Reticulocytes are raised in sickle cell anemia even at baseline.
Question 2 · Hard
A 19-year-old with sickle cell disease types e-positive. After transfusion with e-positive red cells, she develops anti-e, while her DAT and autocontrol stay negative. What is the most likely explanation?
1. AA partial e antigen from a variant RHCE allele
2. BPassive anti-e from a recent plasma transfusion
3. CA false e-positive type caused by a positive DAT
4. DA warm autoantibody with e-like specificity
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Answer: A · A partial e antigen from a variant RHCE allele
People of African ancestry often carry variant RHCE and RHD alleles. Their red cells type e-positive with routine reagents, but the e antigen lacks some epitopes, so exposure to normal e can provoke an alloantibody to the missing part. A negative DAT and autocontrol show that this is not an autoantibody. RH genotyping identifies these patients so that suitable matched units can be chosen.
- B: Nothing suggests plasma was given, and passive antibody would be weak and short-lived.
- C: The DAT is negative, so the e type was not falsely positive from coating.
- D: A warm autoantibody would give a positive DAT and autocontrol.
Question 3 · Medium
In children with sickle cell disease on chronic transfusion for primary stroke prevention, as in the STOP trial, transfusion aims to keep hemoglobin S below:
1. A60%
2. B5%
3. C30%
4. D80%
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Answer: C · 30%
In the STOP trial, regular transfusion that kept hemoglobin S below 30% greatly reduced first strokes in children with abnormal transcranial Doppler velocities. The target is reached by simple transfusion or by automated red cell exchange, which adds less iron. The pretransfusion hemoglobin S is measured by HPLC or electrophoresis to adjust the program. Donor units must be HbS-negative, so that donor sickle trait cells do not add to the measured hemoglobin S.
- A: 60% leaves too much hemoglobin S to protect against stroke.
- B: Below 5% is not needed and would require very intense transfusion.
- D: 80% is close to an untreated patient's level and gives little protection.
Question 4 · Medium
Which test best shows iron loading of the heart in a patient with transfusion-dependent thalassemia?
1. ACardiac MRI T2*
2. BSerum ferritin
3. CLiver biopsy iron concentration
4. DTransferrin saturation
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Answer: A · Cardiac MRI T2*
Cardiac MRI T2* measures iron in the heart muscle: the shorter the T2*, the more iron, and a value below about 10 ms marks a high risk of heart failure. Iron-related heart failure is a leading cause of death in thalassemia major, and heart iron can be high even when ferritin and liver iron look acceptable. Ferritin is a cheap trend marker but is also raised by inflammation and liver disease. Liver iron is now usually measured by MRI rather than biopsy.
- B: Ferritin reflects total body iron and inflammation, not heart iron.
- C: Liver iron does not reliably predict heart iron.
- D: Transferrin saturation shows circulating iron, not tissue stores.
Question 5 · Easy
About how much iron does one unit of red cells add to a transfused patient's body?
1. A20 to 25 mg
2. B1 to 2 g
3. C2 to 5 mg
4. D200 to 250 mg
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Answer: D · 200 to 250 mg
Each unit of red cells holds about 200 to 250 mg of iron in its hemoglobin. The body has no active way to excrete iron, so the iron released when transfused cells are broken down builds up in the liver, heart and endocrine glands. A patient receiving two units a month gains about 5 to 6 g of iron a year, far more than the 1 to 2 mg normally absorbed each day. Chelation is usually started after about 10 to 20 transfusions or when ferritin stays above 1,000 µg/L.
- A: 20 to 25 mg is about one-tenth of the iron in a unit.
- B: 1 to 2 g is the iron in several units, not one.
- C: 2 to 5 mg is close to the iron absorbed from the diet in a day or two.
Question 6 · Hard
A 20-kg girl with thalassemia major in an Abu Dhabi hospital receives 300 mL of red cells (hematocrit 60%) every 3 weeks, about 17 transfusions a year. Taking 1.16 mg of iron per mL of pure red cells, her daily transfusional iron intake is about:
1. A0.03 mg/kg/day
2. B0.49 mg/kg/day
3. C1.35 mg/kg/day
4. D0.81 mg/kg/day
Answer and explanation in LearnFree account
Question 7 · Medium
In transfusion-dependent thalassemia, keeping the pretransfusion hemoglobin at about 95 to 105 g/L (9.5 to 10.5 g/dL) mainly aims to:
1. APrevent alloimmunization to Rh and Kell antigens
2. BSuppress the patient's ineffective erythropoiesis
3. CLower the risk of transfusion-transmitted infection
4. DRemove the need for iron chelation
Answer and explanation in LearnFree account
Question 8 · Easy
Before the first transfusion, which test should be done for a child newly diagnosed with thalassemia major?
1. AA serum IgA level
2. BExtended red cell phenotype or genotype
3. CA platelet antibody screen
4. DA cold agglutinin titer
Answer and explanation in LearnFree account
Question 9 · Hard
A 10-year-old boy with sickle cell anemia (Hb SS) in an Abu Dhabi hospital needs an automated red cell exchange before surgery. He is group O, D-positive, C-negative, E-negative and K-negative, with no alloantibodies. Five leukocyte-reduced group O units are offered: unit 1, C- E- K-, sickle solubility test negative; unit 2, C- E- K-, sickle solubility test positive; unit 3, C+ E- K-, solubility negative; unit 4, C- E- K+, solubility negative; unit 5, C- E- K-, solubility negative. The units suitable for him are:
1. AUnits 1 and 5
2. BUnits 1, 2 and 5
3. CUnits 1, 4 and 5
4. DUnits 1, 3 and 5
Answer and explanation in LearnFree account

Transfusion in thalassemia and sickle cell disease

Eight days after a red cell transfusion, a patient with sickle cell anemia (Hb SS) has pain, fever and dark urine. Which result best shows that the transfused red cells are being destroyed?

A 19-year-old with sickle cell disease types e-positive. After transfusion with e-positive red cells, she develops anti-e, while her DAT and autocontrol stay negative. What is the most likely explanation?

In children with sickle cell disease on chronic transfusion for primary stroke prevention, as in the STOP trial, transfusion aims to keep hemoglobin S below:

Which test best shows iron loading of the heart in a patient with transfusion-dependent thalassemia?

About how much iron does one unit of red cells add to a transfused patient's body?

A 20-kg girl with thalassemia major in an Abu Dhabi hospital receives 300 mL of red cells (hematocrit 60%) every 3 weeks, about 17 transfusions a year. Taking 1.16 mg of iron per mL of pure red cells, her daily transfusional iron intake is about:

In transfusion-dependent thalassemia, keeping the pretransfusion hemoglobin at about 95 to 105 g/L (9.5 to 10.5 g/dL) mainly aims to:

Before the first transfusion, which test should be done for a child newly diagnosed with thalassemia major?