Hot and Cold

A 5-year-old boy presents to the emergency department (ED) with 2 days of fever (temperature 100.7 °F), fatigue, jaundice, and dark urine. The parents note that the child had symptoms of a viral upper respiratory illness 2 weeks before presentation and that he was previously healthy with no history of blood transfusion. In the ED, the child weighs 21.3 kg, and laboratory workup reveals severe anemia with hemoglobin (Hgb) 5.4 g/dL, elevated total bilirubin 5.1 mg/dL, aspartate aminotransferase (AST) 357 U/L (normal range, 8–60 U/L), and lactate dehydrogenase (LDH) 8126 U/L. Serum haptoglobin is undetectable. Urinalysis results are as follows: color, dark; red blood cells (RBCs), 0–3 per high-power field; and urine Hgb, 3+ positive. Notably, the onset of symptoms (fever, fatigue, jaundice, dark urine) was associated with eating a bowl of ice cream. An ethylenediaminetetraacetic acid (EDTA) anticoagulant type and screen sample is submitted to the blood bank along with a request for RBC transfusion.