Incidence, risk factors, and recognition of pseudohyperkalemia in patients with chronic lymphocytic leukemia

Area of Science:

• Hematology
• Clinical Chemistry

Background:

• Pseudohyperkalemia is a laboratory artifact causing falsely elevated serum potassium.
• Fragile leukocytes and high leukocyte counts in chronic lymphocytic leukemia (CLL) predispose patients to pseudohyperkalemia.
• This phenomenon can lead to unnecessary and potentially harmful treatments.

Purpose of the Study:

• To determine the incidence of pseudohyperkalemia in patients with chronic lymphocytic leukemia (CLL).
• To characterize the clinical and laboratory features distinguishing pseudohyperkalemia from true hyperkalemia in CLL patients.
• To assess the documentation and management of pseudohyperkalemia in this patient population.

Main Methods:

• Retrospective observational study of CLL patients with leukocyte counts ≥ 50.0 × 10⁹/L between 2008-2018.
• All hyperkalemic episodes were reviewed, with pseudohyperkalemia defined by normal repeat potassium levels or absence of true hyperkalemia indicators.
• Comparison of leukocyte counts, potassium, LDH levels, and documented risk factors between pseudohyperkalemia and true hyperkalemia cases.

Main Results:

• Of 119 hyperkalemic episodes, 41.2% were identified as pseudohyperkalemia.
• Pseudohyperkalemia cases showed significantly higher leukocyte counts and elevated potassium and LDH levels compared to true hyperkalemia.
• Pseudohyperkalemia was underdiagnosed (8.1% documented) and inappropriately treated in 34.7% of cases, leading to hypokalemia in 6 instances.

Conclusions:

• Pseudohyperkalemia is a frequent occurrence in chronic lymphocytic leukemia patients with high leukocyte counts.
• Clinical awareness and appropriate diagnostic steps are essential to avoid misdiagnosis and overtreatment.
• Further education and standardized protocols are recommended for managing hyperkalemia in CLL patients.