Pseudohyperkalemia Features and Causes

Pseudohyperkalaemia Features:

• Rise in the level of serum potassium that occurs due to excessive leakage of potassium from cells.
• This potassium leakage may occur during or after blood sampling.
• It is thus a laboratory artifact rather than a true biological abnormality.

Pseudohyperkalaemia Typical Causes:

• Haemolysis during venipuncture.
• Excessive tourniquet time
• Excessive fist clenching during phlebotomy (considered to cause efflux of potassium from the muscle cells into the venous system);
• Delay in the processing of the blood specimen.
• People with 'leakier' cell membranes.

Pseudohyperkalaemia Associations:

• Myeloproliferative disorders
• Platelet - platelet activation, thrombocytosis
• Red cell - polycythaemia
• White cell - leukaemia, leukocytosis,

Pseudohyperkalaemia Other Important Points:

• First reported by Hartmann and Mellinkoff in 1955.
• The presence of pseudohyperkalaemia may be masked when it occurs in the presence of real hypokalaemia as potassium can move back into the intracellular space in vitro.
• "... pseudohyperkalemia in serum seems to be the result of two independent and sequential mechanisms: (1) degranulation of platelets, which offers a potassium load to the surrounding serum at the time of clot formation in vitro, and (2) transfer of a part of this potassium load back into blood cells in order to maintain electrolyte and osmotic homeostasis." (1)

Reference:

1) - Nikolaos Sevastos, George Theodossiades, & Athanasios J. Archimandritis. Pseudohyperkalemia in Serum: A New Insight into an Old Phenomenon. Clin Med Res. 2008 May; 6(1): 30–32.

Tags: Haemolysis - Hyperkalaemia - Hypokalaemia - Leukocytosis - Platelet Degranulation - Polycythaemia - Potassium - Pseudohyperkalaemia - Thrombocytosis - VenipunctureTags: Medicine In The News
Posted by Medicalchemy
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