LQCL2618 - CMLE - Alloimmune Complications Following Medical Abortion and Transfusion: A Delayed Hemolytic Transfusion Reaction Case Study-LQCL2617

LQCL2617 - Educational Activity

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The document is a transfusion medicine case study and learning module on delayed hemolytic transfusion reactions (DHTRs). It outlines key objectives: recognizing clinical and laboratory signs of DHTR (jaundice, falling hemoglobin, elevated LDH, indirect hyperbilirubinemia, low haptoglobin), understanding the anamnestic IgG-mediated immune mechanism, appreciating limitations of routine serology (including potentially negative DAT and initially undetectable antibodies), and emphasizing prevention and management strategies such as extended antigen matching and careful transfusion history review.<br /><br />A 30-year-old woman presented to the ED two weeks after a medical abortion and transfusion of two pRBC units with vaginal bleeding, hematuria, suprapubic pain, jaundice, and weakness. Her pre-transfusion antibody screen had been negative. On re-presentation she had clear evidence of hemolysis (marked anemia, undetectable haptoglobin, elevated LDH, predominantly indirect hyperbilirubinemia). Repeat testing showed a panreactive antibody screen, but the DAT was negative for IgG, initially lowering suspicion for transfusion reaction and broadening the differential. Because findings were discordant and serology complex, the sample was sent to an immunohematology reference laboratory, which identified new alloantibodies: anti-E, anti-K, and anti-Jka—confirming DHTR.<br /><br />The case explains that DHTRs typically occur 3–14 days (up to 30 days) post-transfusion due to reactivation of memory B cells from prior sensitization (pregnancy or transfusion), leading to extravascular hemolysis. A negative DAT can occur if antibody levels are low or transfused cells have already been cleared; anti-Jka is highlighted as transient and difficult to detect. Management in this stable patient was supportive care and avoidance of further transfusion, with gradual normalization of hemoglobin and hemolysis markers. The module stresses prevention via extended phenotyping/genotyping (especially in females of childbearing age), documentation of antibodies, medical alert systems, and early referral to reference labs for complex antibody workups.

Keywords

delayed hemolytic transfusion reaction

DHTR

transfusion medicine case study

anamnestic IgG response

alloantibodies

anti-E

anti-K

anti-Jka

negative direct antiglobulin test

extended antigen matching