Forty minutes into a red cell transfusion, a patient's temperature rises from 37.0 °C to 38.4 °C with chills. Blood pressure is stable. The clerical check is correct, the post-transfusion plasma is clear and the DAT is negative. The most likely diagnosis is:

Febrile nonhemolytic transfusion reaction

Anaphylactic transfusion reaction

Acute hemolytic transfusion reaction

Transfusion-related acute lung injury

In a reaction workup, the clerical check is correct and the ABO/Rh retype matches. The pretransfusion DAT was negative, but the post-transfusion DAT is positive with IgG in a mixed-field pattern. What should be done next?

Test an eluate and both samples for antibodies

Stop testing; the retype matched

Retype the patient's ABO group again

Report a febrile nonhemolytic reaction and stop

Which finding best separates an anaphylactic transfusion reaction from an acute hemolytic reaction?

Airway signs and hypotension without fever

Oozing of blood from IV and wound sites

A positive DAT on the post-transfusion sample

Fever, red urine and pain in the back

A patient has an acute hemolytic reaction to group A red cells. Which result shows that a wrong-blood-in-tube error caused it?

The pre-transfusion tube is A; a new sample is O

The post-transfusion DAT is negative with anti-IgG

Both antibody screens are negative

The unit's segment types as labeled

A patient taking an ACE inhibitor becomes hypotensive within minutes of starting a platelet transfusion. There is no fever, rash or wheezing, and blood pressure recovers soon after the transfusion is stopped. The most likely cause is:

A hypotensive reaction from bradykinin

An acute hemolytic transfusion reaction

Transfusion-associated circulatory overload

Adverse effects: immunologic reactions

18 ASCP MLS practice questions on Adverse effects: immunologic reactions, part of Blood Banking. The first 18 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 · Medium
Forty minutes into a red cell transfusion, a patient's temperature rises from 37.0 °C to 38.4 °C with chills. Blood pressure is stable. The clerical check is correct, the post-transfusion plasma is clear and the DAT is negative. The most likely diagnosis is:
1. AFebrile nonhemolytic transfusion reaction
2. BAnaphylactic transfusion reaction
3. CAcute hemolytic transfusion reaction
4. DTransfusion-related acute lung injury
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Answer: A · Febrile nonhemolytic transfusion reaction
Fever and chills without hemolysis, hypotension or breathing problems fit a febrile nonhemolytic reaction. The clear plasma and negative DAT make hemolysis unlikely, but FNHTR remains a diagnosis of exclusion. If the fever is high, or there are rigors or hypotension, the unit and the patient should be cultured for bacterial contamination. The transfusion is not restarted with the same unit.
- B: Anaphylaxis causes hypotension and airway symptoms, usually without fever.
- C: Hemolysis is unlikely with clear plasma, a negative DAT and stable blood pressure.
- D: TRALI causes hypoxemia and lung infiltrates.
Question 2 · Hard
In a reaction workup, the clerical check is correct and the ABO/Rh retype matches. The pretransfusion DAT was negative, but the post-transfusion DAT is positive with IgG in a mixed-field pattern. What should be done next?
1. AStop testing; the retype matched
2. BRetype the patient's ABO group again
3. CReport a febrile nonhemolytic reaction and stop
4. DTest an eluate and both samples for antibodies
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Answer: D · Test an eluate and both samples for antibodies
A newly positive DAT with mixed-field reactions suggests that transfused red cells are coated with antibody. An eluate identifies the antibody, and antibody screens on the pretransfusion and post-transfusion samples show whether it was missed or is new. The antigen types of the transfused units are then checked against the specificity. This points to a hemolytic reaction from an antibody other than ABO.
- A: A matching retype does not explain the newly positive DAT.
- B: The ABO retype already matched; the next step is the antibody workup.
- C: A positive DAT must be explained before a febrile reaction is reported.
Question 3 · Medium
Which finding best separates an anaphylactic transfusion reaction from an acute hemolytic reaction?
1. AOozing of blood from IV and wound sites
2. BAirway signs and hypotension without fever
3. CA positive DAT on the post-transfusion sample
4. DFever, red urine and pain in the back
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Answer: B · Airway signs and hypotension without fever
Anaphylaxis starts within minutes, with bronchospasm, laryngeal edema, hypotension and often hives, but no fever and no hemolysis. It is caused by antibodies to donor plasma proteins, classically anti-IgA in IgA-deficient patients and, in some East Asian patients, anti-haptoglobin in haptoglobin deficiency. Treatment is stopping the transfusion and giving epinephrine. Acute hemolytic reactions bring fever, hemoglobinuria and a positive DAT.
- A: Oozing suggests DIC, which can complicate hemolytic reactions.
- C: A positive DAT points to antibody-coated red cells, as in hemolysis.
- D: Fever, red urine and back pain point to hemolysis.
Question 4 · Hard
A patient has an acute hemolytic reaction to group A red cells. Which result shows that a wrong-blood-in-tube error caused it?
1. AThe post-transfusion DAT is negative with anti-IgG
2. BBoth antibody screens are negative
3. CThe unit's segment types as labeled
4. DThe pre-transfusion tube is A; a new sample is O
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Answer: D · The pre-transfusion tube is A; a new sample is O
If the pretransfusion sample was actually another patient's blood, it will type differently from a new sample drawn correctly from the patient. Here the patient is group O but was crossmatched using a group A sample. Such errors are why many hospitals require a second sample, or electronic identification, before issuing non-group O red cells. Other samples collected at the same time should be checked too.
- A: A negative DAT does not identify a sample error.
- B: Negative antibody screens are expected with an ABO error.
- C: A correctly labeled unit does not exclude a patient sample error.
Question 5 · Hard
A patient taking an ACE inhibitor becomes hypotensive within minutes of starting a platelet transfusion. There is no fever, rash or wheezing, and blood pressure recovers soon after the transfusion is stopped. The most likely cause is:
1. AA hypotensive reaction from bradykinin
2. BAn acute hemolytic transfusion reaction
3. CTransfusion-associated circulatory overload
4. DA septic transfusion reaction
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Answer: A · A hypotensive reaction from bradykinin
Bradykinin generated during collection or filtration can lower blood pressure, and ACE inhibitors slow its breakdown. Hypotensive reactions start quickly and resolve soon after the transfusion is stopped, without fever or allergic signs. Hemolysis, sepsis and anaphylaxis must still be excluded. Bedside leukocyte filters were linked to such reactions before prestorage leukoreduction became standard.
- B: Hemolysis would not resolve so quickly and usually brings fever and hemoglobinuria.
- C: Circulatory overload raises blood pressure.
- D: Sepsis brings fever and rigors and does not resolve quickly on stopping.
Question 6 · Medium
Under the CDC NHSN hemovigilance criteria, a febrile nonhemolytic transfusion reaction needs a temperature of at least 38 °C (100.4 °F) and a rise from the pretransfusion value of at least:
1. A1 °C (1.8 °F)
2. B0.5 °C (0.9 °F)
3. C2 °C (3.6 °F)
4. D3 °C (5.4 °F)
Answer and explanation in LearnFree account
Question 7 · Easy
A patient develops chills and back pain 10 minutes into a red cell transfusion. What should the nurse do first?
1. AGive an antipyretic and continue the transfusion
2. BFinish the unit quickly, then report the symptoms
3. CStop the transfusion and keep the line open with saline
4. DSlow the infusion rate and recheck the patient in an hour
Answer and explanation in LearnFree account
Question 8 · Medium
Ten minutes into a plasma transfusion, a patient develops a few itchy hives on one arm. Vital signs are normal and there is no wheezing. Which action is acceptable?
1. AContinue the transfusion without pausing
2. BStop it and start a full hemolytic workup
3. CCancel all future plasma orders for this patient
4. DPause, treat with an antihistamine, then resume
Answer and explanation in LearnFree account
Question 9 · Hard
Two hours after a plasma transfusion, a patient has severe hypoxemia (SpO2 84% on room air), fever, low blood pressure and new bilateral infiltrates. The neck veins are flat and BNP is normal. What should the blood bank do?
1. ATest the patient for anti-IgA antibodies
2. BRepeat the crossmatch with every remaining unit issued
3. CNotify the supplier to test the donors for antibodies
4. DCulture the bag and take no further action
Answer and explanation in LearnFree account
Question 10 · Hard
Ten days after receiving fresh, nonirradiated red cells donated by her son, a woman develops fever, a skin rash, diarrhea, abnormal liver tests and falling blood counts. The most likely diagnosis is:
1. ATransfusion-associated GVHD
2. BDrug rash with viral hepatitis
3. CPost-transfusion purpura
4. DDelayed hemolytic transfusion reaction
Answer and explanation in LearnFree account
Question 11 · Hard
Ten days after transfusion, a patient's antibody screen is newly positive with anti-Fya, and the DAT is positive with IgG. The hemoglobin is stable, and bilirubin and LD are normal. This is best classified as:
1. AA delayed serologic transfusion reaction
2. BWarm autoimmune hemolytic anemia
3. CA delayed hemolytic transfusion reaction
4. DAn acute hemolytic transfusion reaction
Answer and explanation in LearnFree account
Question 12 · Medium
The blood bank receives a report of a suspected transfusion reaction. What is the first laboratory step?
1. ACulture of the remaining blood in the bag
2. BA repeat crossmatch of all units issued that day
3. CA clerical check of labels and records
4. DAn antibody panel on the post-transfusion sample
Answer and explanation in LearnFree account
Question 13 · Easy
Hives (urticaria) during a plasma transfusion are usually caused by:
1. ABacterial endotoxin in the component
2. BRecipient IgE against donor plasma proteins
3. CCytokines released from donor white cells
4. DRecipient antibodies to donor red cells
Answer and explanation in LearnFree account
Question 14 · Medium
In a reaction workup, the post-transfusion plasma is pink, while the pretransfusion plasma was clear. If the sample was drawn without difficulty, this suggests:
1. AA febrile nonhemolytic reaction
2. BIntravascular hemolysis since the transfusion
3. CA mild allergic reaction
4. DTransfusion-associated circulatory overload
Answer and explanation in LearnFree account
Question 15 · Hard
Ninety minutes after receiving one apheresis platelet unit and two plasma units, a 58-year-old man develops severe hypoxemia (SpO2 82% on room air), fever, hypotension and new bilateral infiltrates. BNP is normal and he is not fluid overloaded. The donors are tested. Recipient HLA type: A1, A3; B8, B44; DR4, DR15. Donor 1, male (plasma): no HLA or HNA antibodies. Donor 2, female (platelets): anti-HLA-A2 and anti-HLA-DR4. Donor 3, female, never pregnant (plasma): no HLA or HNA antibodies. Which conclusion is best supported?
1. ANo donor; the findings fit TACO best
2. BDonor 2, through cognate anti-HLA-A2
3. CDonor 2, through cognate anti-HLA-DR4
4. DDonor 3, as a female plasma donor
Answer and explanation in LearnFree account
Question 16 · Hard
A 16-year-old boy with sickle cell disease received 2 units of C-, E- and K-negative red cells 8 days ago for acute chest syndrome; his hemoglobin rose from 6.9 to 9.2 g/dL (69 to 92 g/L). He now has severe pain and dark urine. Results: hemoglobin 5.4 g/dL (54 g/L), absolute reticulocytes 60 x 10^3/µL (his usual value is 300 x 10^3/µL), LD 2,100 U/L, and HbA by HPLC 2% (34% after the transfusion). The DAT, antibody screen and eluate are all negative. The most likely diagnosis is:
1. AParvovirus B19 aplastic crisis
2. BHyperhemolysis syndrome
3. CDelayed serologic transfusion reaction
4. DAcute hemolysis from an ABO error
Answer and explanation in LearnFree account
Question 17 · Medium
The flowchart shows a laboratory workup of a suspected transfusion reaction. Which step belongs in the dashed box?
Figure: MedExams
1. ACulture the unit bag and the patient's blood
2. BTest the donor plasma for HLA antibodies
3. CRepeat ABO/Rh, antibody screen and crossmatch
4. DTest the patient for IgA deficiency
Answer and explanation in LearnFree account
Question 18 · Hard
During a red cell transfusion a patient develops fever, chills, hypotension and red urine. The post-transfusion sample has hemolyzed plasma and a positive DAT. What is the most likely cause?
1. AAn allergic reaction to donor plasma proteins
2. BTransfusion-associated circulatory overload
3. CA febrile non-hemolytic transfusion reaction
4. DAn acute hemolytic reaction, usually ABO-incompatible
Answer and explanation in LearnFree account

Adverse effects: immunologic reactions

Forty minutes into a red cell transfusion, a patient's temperature rises from 37.0 °C to 38.4 °C with chills. Blood pressure is stable. The clerical check is correct, the post-transfusion plasma is clear and the DAT is negative. The most likely diagnosis is:

In a reaction workup, the clerical check is correct and the ABO/Rh retype matches. The pretransfusion DAT was negative, but the post-transfusion DAT is positive with IgG in a mixed-field pattern. What should be done next?

Which finding best separates an anaphylactic transfusion reaction from an acute hemolytic reaction?

A patient has an acute hemolytic reaction to group A red cells. Which result shows that a wrong-blood-in-tube error caused it?

A patient taking an ACE inhibitor becomes hypotensive within minutes of starting a platelet transfusion. There is no fever, rash or wheezing, and blood pressure recovers soon after the transfusion is stopped. The most likely cause is:

Under the CDC NHSN hemovigilance criteria, a febrile nonhemolytic transfusion reaction needs a temperature of at least 38 °C (100.4 °F) and a rise from the pretransfusion value of at least:

A patient develops chills and back pain 10 minutes into a red cell transfusion. What should the nurse do first?

Ten minutes into a plasma transfusion, a patient develops a few itchy hives on one arm. Vital signs are normal and there is no wheezing. Which action is acceptable?

Two hours after a plasma transfusion, a patient has severe hypoxemia (SpO2 84% on room air), fever, low blood pressure and new bilateral infiltrates. The neck veins are flat and BNP is normal. What should the blood bank do?

Ten days after receiving fresh, nonirradiated red cells donated by her son, a woman develops fever, a skin rash, diarrhea, abnormal liver tests and falling blood counts. The most likely diagnosis is:

Ten days after transfusion, a patient's antibody screen is newly positive with anti-Fya, and the DAT is positive with IgG. The hemoglobin is stable, and bilirubin and LD are normal. This is best classified as:

The blood bank receives a report of a suspected transfusion reaction. What is the first laboratory step?

Hives (urticaria) during a plasma transfusion are usually caused by:

In a reaction workup, the post-transfusion plasma is pink, while the pretransfusion plasma was clear. If the sample was drawn without difficulty, this suggests:

The flowchart shows a laboratory workup of a suspected transfusion reaction. Which step belongs in the dashed box?

During a red cell transfusion a patient develops fever, chills, hypotension and red urine. The post-transfusion sample has hemolyzed plasma and a positive DAT. What is the most likely cause?