Mild hyponatremia Biochemical finding of a serum sodium concentration between130 and 135 mmol/l Moderate hyponatremia Biochemical finding of a serum sodium concentration between 125 and 129 mmol/l Severe hyponatremia Biochemical finding of a serum sodium concentration <125 mmol/l

Table 1: Definition of hyponatremia based on biochemical severity [12].