Transfusion reaction

Transfusion reaction or mismatched transfusion is suspected, immediate laboratory investigations are crucial to identify the cause, prevent further complications, and ensure the safety of future transfusions. The workup involves a combination of clinical observation and laboratory tests, as many transfusion reactions can mimic other medical conditions. Below are the steps involved in investigating a transfusion reaction:

Transfusion Reaction:

1. Table of contents

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   Immediate Actions

When a transfusion reaction is suspected:

• Stop the transfusion immediately.
• Keep the intravenous (IV) line open with normal saline.
• Notify the blood bank and the attending physician.
• Send the blood unit and patient samples to the laboratory for further testing.

2. Clinical Evaluation

• Symptoms: Record the patient’s symptoms (fever, chills, hypotension, dark urine, rash, breathing difficulties, etc.).
• Physical Examination: Evaluate the patient for signs of hemolysis, anaphylaxis, respiratory distress, or circulatory overload.

3. Basic Laboratory Investigations

The following tests are performed on the patient’s and the remaining donor’s blood.

• ABO and Rh Typing:

  • Objective: To check whether a mismatched ABO or Rh transfusion occurred.
  • Procedure: Repeat the patient’s ABO and Rh typing and compare it with the donor unit.

• Direct Antiglobulin Test (DAT or Direct Coombs Test):

  • Objective: To detect if the patient’s red blood cells are coated with antibodies or complement.
  • Procedure: The patient’s red blood cells are tested with an anti-human globulin reagent to check for bound antibodies.
  • Interpretation:
    • Positive DAT: Indicates an immune-mediated hemolytic transfusion reaction (e.g., due to ABO incompatibility, alloantibodies, or delayed hemolytic reaction).
    • Negative DAT: Rules out immune-mediated hemolysis but does not exclude non-immune causes of hemolysis.

• Visual Inspection for Hemolysis:

  • Objective: To detect free haemoglobin in plasma or urine, which indicates red blood cell destruction.
  • Procedure: Centrifuge a fresh blood sample and inspect the plasma.
  • Interpretation:
    • Pink or red plasma: Indicates hemolysis.
    • Clear plasma: Hemolysis is unlikely.
  • Urine sample: Can be checked for hemoglobinuria, which is consistent with intravascular hemolysis.
• Crossmatch (Recheck):
  • Objective: To confirm compatibility between the donor and recipient.
  • Procedure: Repeat major crossmatching (recipient plasma against donor red cells).
  • Interpretation:
    • Compatible crossmatch: Suggests no ABO/Rh mismatch but does not rule out minor antigen incompatibility.
    • Incompatible crossmatch: Confirms the transfusion reaction due to a mismatch.

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4. Additional Laboratory Tests

• Hemoglobin and Hematocrit:

  • Objective: To assess the red blood cell destruction level and the patient’s response to transfusion.
  • Interpretation:
    • A drop in haemoglobin/hematocrit post-transfusion suggests hemolysis or ineffective transfusion.

• Serum Bilirubin:

  • Objective: To evaluate for hemolysis.
  • Interpretation:
    • Increased indirect (unconjugated) bilirubin: Indicates hemolysis, as the liver processes the by-products of destroyed RBCs.

• Lactate Dehydrogenase (LDH):

  • Objective: LDH is released from destroyed RBCs and is elevated in cases of hemolysis.
  • Interpretation: Elevated LDH levels are indicative of cell breakdown and hemolysis.

• Haptoglobin:

  • Objective: Haptoglobin binds free haemoglobin released from destroyed red blood cells.
  • Interpretation:
    • Low haptoglobin: Suggests hemolysis, as free haemoglobin overwhelms haptoglobin binding capacity.

• Reticulocyte Count:

  • Objective: To evaluate the bone marrow’s response to anaemia caused by hemolysis.
  • Interpretation: A high reticulocyte count suggests the body is trying to replace the destroyed RBCs.

• Coagulation Profile:

  • Objective: To check for signs of disseminated intravascular coagulation (DIC), which may occur in severe hemolytic reactions.
  • Tests: PT (Prothrombin Time), aPTT (Activated Partial Thromboplastin Time), and D-dimer.
  • Interpretation:
    • Abnormal clotting times and elevated D-dimer indicate DIC, a serious complication of severe transfusion reactions.

• Blood Cultures:

  • Objective: To rule out bacterial contamination of the blood unit, especially in febrile reactions or when symptoms suggest sepsis.
  • Interpretation:
    • Positive blood cultures suggest bacterial contamination of the transfused blood product, a medical emergency.

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5. Specialized Tests

• Antibody screening:

  • Objective: Identify any pre-existing or newly developed antibodies against minor blood group antigens (e.g., Kell, Duffy, Kidd).
  • Procedure: The patient’s serum is tested against a panel of red cells with known antigens.
  • Interpretation: Antibodies suggest an alloimmune reaction, possibly causing a delayed hemolytic transfusion reaction (DHTR).

• Investigation for TRALI (Transfusion-Related Acute Lung Injury):

  • Objective: To diagnose TRALI, a potentially fatal reaction that causes respiratory distress.
  • Tests:
    • Chest X-ray: To check for pulmonary oedema (lung fluid).
    • Donor antibodies: Testing for anti-leukocyte antibodies in donor plasma.
    • Exclusion of other causes of pulmonary oedema (e.g., circulatory overload).

• Investigation for TACO (Transfusion-Associated Circulatory Overload):

  • Objective: To diagnose TACO, where excess fluid from the transfusion overloads the heart.
  • Tests:
    • Chest X-ray: To check for signs of pulmonary oedema and heart failure.
    • Clinical evaluation of blood pressure, heart rate, and oxygen levels.

6. Reporting and Documentation

After completing the laboratory investigation, all findings should be:

• Documented in the patient’s medical records.
• Reported to the blood bank and transfusion services to prevent reaction recurrence in future transfusions.
• Communicated with the healthcare provider to adjust treatment if needed.

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Management Based on Findings:

• ABO or Rh Mismatch:
  • Immediate cessation of transfusion.
  • Supportive care for the patient, including fluids, diuretics (to promote kidney function), and monitoring for hemolysis.
  • Reporting to prevent future errors.
• Hemolytic Transfusion Reaction (Immune-Mediated):
  • Stop transfusion and provide supportive care.
  • Monitor the patient closely for kidney function, DIC, and cardiovascular instability.
  • Administer corticosteroids or immunosuppressive therapy in severe cases.
• Febrile Non-Hemolytic Reaction:
  • Stop transfusion, monitor the patient, and administer antipyretics (fever reducers).
  • In future transfusions, consider using leukocyte-reduced blood products.
• Allergic or Anaphylactic Reactions:
  • Administer antihistamines or corticosteroids for mild reactions.
  • In cases of anaphylaxis, immediate epinephrine administration is required.
  • Premedication with antihistamines or washed red blood cells may be considered for future transfusions.
• Bacterial Contamination:
  • Discontinue the transfusion.
  • Administer broad-spectrum antibiotics immediately.
  • Monitor for sepsis and organ failure.