SHM Converge Scientific Abstract ePoster Gallery-Sample, Not Serum: Identifying Spurious Hypokalemia

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This case describes a 45-year-old man with generalized weakness, somnolence, and visual changes who was found to have acute myeloid leukemia (AML) with extreme leukocytosis (WBC 402,000/µL). His venous potassium was critically low at 1.7 mmol/L, but the clinical picture did not fit true severe hypokalemia: he had no cardiac or gastrointestinal symptoms, no classic ECG changes, and point-of-care (POC) potassium was higher at 3.0 mmol/L. He also had anemia, thrombocytopenia, acute kidney injury, metabolic alkalosis, elevated LDH, and splenomegaly. Peripheral smear confirmed AML, and he was started on cytarabine and leukapheresis.<br /><br />The key teaching point is spurious hypokalemia, also called pseudohypokalemia. In patients with marked leukocytosis, especially hematologic malignancies such as AML, metabolically active leukemic blasts can continue to take up potassium in vitro after blood is drawn. This lowers the measured potassium in delayed venous samples, even though the patient’s true in vivo potassium is normal. POC testing helps avoid this artifact because the sample is analyzed immediately.<br /><br />This case highlights the importance of interpreting lab values in clinical context rather than treating a number alone. Recognizing spurious hypokalemia is crucial because unnecessary potassium replacement can cause dangerous rebound hyperkalemia, particularly in patients at risk for tumor lysis syndrome. In this patient, that risk became real when repeat POC potassium rose to 5.3–5.8 mmol/L after treatment, requiring hyperkalemia management.<br /><br />Overall, the report emphasizes careful correlation of symptoms, ECG findings, and testing method when evaluating electrolyte abnormalities in patients with extreme leukocytosis.

Asset Subtitle

Zoya Khan

Meta Tag

Author List Adriana Morales Rivera, Graciela M. Luna, Umair Ahmed, Zoya Khan

Category Clinical Vignettes

Concept Leukocytosis

Concept Acute Leukemia

Concept Pseudohypokalemia

Concept Tumor Lysis Syndrome

Concept Leukemic Blasts

Distinguished Non-Finalist

Presenter Organization Lakeland Regional Health

Presenting Author Zoya Khan

Track Adult

Keywords

acute myeloid leukemia

extreme leukocytosis

spurious hypokalemia

pseudohypokalemia

point-of-care potassium

tumor lysis syndrome

hyperkalemia

leukapheresis

cytarabine

electrolyte artifact

Leukocytosis

Acute Leukemia

Pseudohypokalemia

Tumor Lysis Syndrome

Leukemic Blasts