Unusual discrepancy between S(pO(2)) and S(aO(2)) in a 31-year-old man with chronic myelogenous leukemia.

Hyperleukocytosis and thrombocytosis may develop in hematological disorders, including acute myelogenous or lymphoblastic leukemia, chronic leukemias in accelerated phase, and polycythemia vera. In such clinical scenarios, patients are at risk for hypoxemia, either true or spurious.1 The causes of true hypoxemia may include pulmonary leukostasis, pneumonia, and pulmonary embolism.1 However, sometimes the bloodstream oxygen saturation of the hemoglobin measured by a pulse oximeter (SpO2) may be substantially higher than that measured by a laboratory method (SaO2) in patients with hyperleukocytosis or extreme thrombocytosis.2-5 These patients are actually not in a hypoxemic status. Spurious hypoxemia or pseudohypoxemia is used to describe this phenomenon.3-5 Here we report such a condition in a patient with chronic myelogenous leukemia when he was in an accelerated phase.