Pseudohyperkalemia in a patient with chronic lymphoblastic leukemia and tumor lysis syndrome

Purpose:Recognition of pseudohyperkalemia is essential to prevent medical mismanagement of erroneous hyperkalemia. The purpose of this case is to describe pseudohyperkalemia attributed to malignant leucocytosis in a patient with chronic lymphoblastic leukemia and tumor lysis syndrome. Methods for determination of pseudohyperkalemia are discussed.Summary:A 75-year-old male with progressive chronic lymphoblastic leukemia was hospitalized for medical evaluation and chemotherapy administration. Notable laboratory findings included white blood cell count of 479 × 103 cells/µL (4.00 × 103 cells/µL–10.80 × 103 cells/µL) with 95% lymphocytes (20%–50%) and 5% blasts (zero) present in the differential, serum potassium 9.8 mM/L (3.4 mM/L–5.0 mM/L), uric acid of 11.8 mg/dL (3.5 mg/dL–8.0 mg/dL), serum creatinine 1.47 mg/dL (0.60 mg/dL–1.30 mg/dL), and lactate dehydrogenase of 2529 IU/L (100 IU/L–220 IU/L). The patient was anemic (Hb 7.6 g/dL (14.0 g/dL–18.0 g/dL)) and thrombocytopenic (17 × 103 platelets/μL (140 × 10...