Acute Intravascular Hemolytic Transfusion Reaction from an ABO-Incompatible Unit
A 63-year-old man with myelodysplastic syndrome and Hb 71 g/L is transfused one unit of packed red cells for symptomatic anemia. Fifteen minutes into the transfusion he develops rigors, fever 39.1°C, flank pain, and dark urine. The transfusion is stopped after approximately 60 mL. His pretransfusion sample is group O RhD-negative; the unit label reads group A RhD-positive. The post-transfusion sample shows pink plasma, Hb 68 g/L, bilirubin 48 µmol/L, LDH 1,200 U/L, and a positive direct antiglobulin test (DAT) with polyspecific and anti-C3d reagents. The laboratory scientist must direct the immediate workup, interpret the findings, and identify the system failures that allowed the error. He is oliguric; urine output 15 mL/h. No other medications were given in the preceding 6 hours.
1. List the immediate actions and laboratory workup for this suspected transfusion reaction.
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Stop the transfusion immediately, keep the IV line open with 0.9% saline using new tubing, and assess vital signs, urine output, and bleeding. Notify the transfusion service and the clinician. Return the unit, tubing, and all paperwork, and perform a clerical check of patient identity, sample, and unit label. Collect post-transfusion EDTA and clotted samples: repeat ABO/Rh and antibody screen, DAT, plasma free hemoglobin, haptoglobin, bilirubin, LDH, renal function, PT/INR, fibrinogen, D-dimer, and urinalysis for hemoglobin. Check the unit segment for ABO. The group O recipient receiving a group A unit is an ABO-incompatible transfusion; a DAT positive with anti-C3d and pink plasma supports intravascular hemolysis. Report as a suspected acute hemolytic transfusion reaction and initiate monitoring for renal failure and DIC.
2. Interpret the laboratory findings and explain the clinical risks.
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Rigor, fever, flank pain, dark urine, and oliguria are classic for an acute intravascular hemolytic reaction. Recipient anti-A IgM fixes complement; the DAT is positive with anti-C3d, and complement-mediated lysis releases free hemoglobin, raising LDH and bilirubin and producing hemoglobinuria. The Hb of 68 g/L is not much lower than the pretransfusion 71 g/L because only about 60 mL was given and because free hemoglobin is measured as total Hb; falling haptoglobin and rising LDH and bilirubin are more informative. Pink plasma reflects free hemoglobin. Complications include acute kidney injury, DIC, shock, and death. Monitor urine output, creatinine, platelets, coagulation, and blood pressure. Management is supportive: saline, maintain urine output, treat DIC, and avoid nephrotoxins. The small volume improves prognosis but does not remove the need for close monitoring.
3. What system failures may have allowed this error, and what corrective actions should follow?
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The immediate cause is bedside administration of a group A unit to a group O recipient. Possible system failures include issuing the unit for another patient without an identity check at the bedside, single-person verification or a barcode override, mislabeling of the pretransfusion sample or a wrong-blood-in-tube event, look-alike names, an unlabeled unit in the refrigerator, or failure to scan both the patient wristband and the unit. Corrective actions include independent two-person bedside verification of identity and ABO, barcode scanning at the bedside, no override without supervisor approval, root-cause analysis, retraining and competency assessment, audits of transfusion episodes, and reporting to the national hemovigilance system. Review sample collection and labeling, and consider a formal failure-mode analysis of the entire transfusion pathway.