Critically elevated potassium in a 55-year-old female with chronic lymphocytic leukemia

Abstract

Hyperkalemia in specimens from patients with chronic lymphocytic leukemia (CLL) may be due to tumor lysis syndrome (TLS) or specimen processing. This report describes a 55-year-old Caucasian woman with CLL who presented to an outside hospital with hyperkalemia and was transferred to a second hospital. Initial evaluation on the core laboratory chemistry analyzer (the VITROS 5600) and the ABL90 FLEX blood gas analyzer showed markedly elevated levels of potassium (K+). TLS was subsequently diagnosed, and dialysis was initiated. However, follow-up K+ measurements in whole blood (WB) yielded low levels that were unexpected after a single dialysis treatment. We then discovered that the initially elevated K+ level was from centrifuged plasma specimens and concluded that it indicated pseudohyperkalemia, likely from centrifugation. This case demonstrates that medical teams need be alert to potentially false K+ results in patients with elevated white blood cell counts. WB specimens are preferable, and steps to minimize trauma to the specimen and immediate analysis using blood gas instruments are recommended.