Reverse pseudohyperkalemia: Verify potassium levels before initiating treatment

Abstract

Hyperkalemia is a complex laboratory abnormality. There are varying degrees of true hyperkalemia, pseudohyperkalemia, and even reverse pseudohyperkalemia which must be distinguished from one another. We present a case of reverse pseudohyperkalemia in an elderly male with a hematologic malignancy found to have an elevated potassium level on admission. Both plasma and serum levels were measured, plasma level was high while serum levels were normal, and a diagnosis of reverse pseudohyperkalemia was made. Awareness and increased suspicion result in rapid diagnosis, and prevent overtreatment and iatrogenic complications.

Pseudohyperkalemia Associated With Leukemia

“…This has been shown in several studies by findings of higher plasma potassium levels in the simultaneously collected samples of heparinized tubes compared to non-heparinized tubes [ 8 ]. There is also a directly proportional relationship between potassium concentration and the amount of heparin in the tubes [ 8 ]. Hence, high potassium in asymptomatic leukemia patients with no EKG changes requires careful evaluation before treatment is begun.…”

“…It is also thought that there may be leakage of potassium from fragile white blood cells in patients with leukemia, leading to falsely elevated potassium. This is theorized to occur due to a lack of energy to maintain sodium/ potassium adenosine triphosphatase activity for the collected large number of white cells in-vitro, resulting in the release of potassium contributing to false hyperkalemia [ 2 , 5 , 7 - 8 ]. Another proposed mechanism is that the heparin in the collection tube causes damage to the membranes of the brittle malignant cells [ 8 ].…”

“…This is theorized to occur due to a lack of energy to maintain sodium/ potassium adenosine triphosphatase activity for the collected large number of white cells in-vitro, resulting in the release of potassium contributing to false hyperkalemia [ 2 , 5 , 7 - 8 ]. Another proposed mechanism is that the heparin in the collection tube causes damage to the membranes of the brittle malignant cells [ 8 ]. This has been shown in several studies by findings of higher plasma potassium levels in the simultaneously collected samples of heparinized tubes compared to non-heparinized tubes [ 8 ].…”

“…Another proposed mechanism is that the heparin in the collection tube causes damage to the membranes of the brittle malignant cells [ 8 ]. This has been shown in several studies by findings of higher plasma potassium levels in the simultaneously collected samples of heparinized tubes compared to non-heparinized tubes [ 8 ]. There is also a directly proportional relationship between potassium concentration and the amount of heparin in the tubes [ 8 ].…”