Table 1.

Causes of pseudohyperkalaemia (the serum potassium exceeds the plasma potassium by more than 0.4 mmol/L)

• Prolonged tourniquet application prior to venepuncture

• Haemolysis during venepuncture

• Samples undergoing centrifugation prior to clot formation

• Leukocytosis (white cell count greater than >70 000/mm3)

• Thrombocytosis

• Familial pseudohyperkalaemia

• Hereditary spherocytosis