Hyperleukocytosis in acute myeloid leukemia (AML) can cause life-threatening complications and rarely “leukocyte larceny,” in which markedly elevated blasts consume oxygen in arterial blood gas (ABG) samples, producing spuriously low PaO₂ values. We report an 82-year-old man with newly diagnosed AML and WBC 310.8 × 109/L who developed hypoxic respiratory failure requiring intubation. Despite low post-intubation PaO2, pulse oximetry remained consistent with adequate oxygenation, suggesting partially spurious hypoxemia in the setting of true respiratory compromise. Cytoreduction was initiated; however, his course was complicated by tumor lysis syndrome, renal failure, shock, and death. This case highlights the diagnostic pitfall of leukocyte larceny that may complicate clinical decision-making and emphasizes the importance of correlating ABG results with pulse oximetry and considering rapid sample processing or cooling to reduce in vitro oxygen consumption.
Tactuk et al. (Wed,) studied this question.