Pseudohyperkalemia in a Patient With Chronic Lymphocytic Leukemia

Area of Science:

• Hematology
• Clinical Chemistry
• Internal Medicine

Background:

• Hyperkalemia is a critical electrolyte imbalance with serious cardiac implications.
• Distinguishing true hyperkalemia from pseudohyperkalemia is essential for appropriate patient management.

Observation:

• A 63-year-old male with chronic lymphocytic leukemia (CLL) presented with markedly elevated serum potassium levels (up to 8.4 mmol/L).
• Despite high serum potassium, venous blood gas analysis revealed normal plasma potassium (3.7-4.4 mmol/L), indicating pseudohyperkalemia.

Findings:

• Mechanical stress, such as blood sample centrifugation, can lyse fragile white blood cells in CLL patients.
• This lysis releases intracellular potassium, leading to falsely elevated serum potassium concentrations (pseudohyperkalemia).

Implications:

• Clinicians must be aware of pseudohyperkalemia in CLL patients with high white blood cell counts.
• Recognizing spurious laboratory values prevents unnecessary treatments and invasive diagnostic procedures.
• This case highlights the importance of specific diagnostic methods like venous blood gas analysis to confirm true electrolyte disturbances.