Hyperkalaemia can occur due to: Artefactual causes, such as poor venepuncture, contamination, haemolysis, or the presence of a high count of platelets in serum collections, Redistribution (e.g. acidosis, haemolytic disorders, cell lysis), decreased renal excretion (e.g. in renal failure), mineralocorticoid deficiency, potassium sparing diuretics. Hypokalaemia may be due to: Artefactual causes (e.g. contamination from drip sites), redistribution (e.g. alkalosis), insulin treatment (causes uptake into cells), inadequate intake (e.g. anorexia nervosa), abnormal losses e.g. gastrointestinal (vomiting, diarrhoea, laxative abuse), or renal (diuretic therapy, Cushings, hyperaldosteronism)
Pseudohyperkalaemia - seen in patients with high platelets/WCC, when a serum sample clots potassium is released causing a falsely elevated potassium result. Contamination - EDTA is used as an anticoagulant, and is normally in the form of its potassium salt. This can contaminate serum samples, giving a raised potassium, low corrected calcium and possibly low ALP activity. Haemolysis - potassium is an intracellular cation, and is released during in vitro haemolysis. Hence, potassium results will not be reported on haemolysed samples.
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