Normal Serum Sodium for a 1-Year-Old
The normal serum sodium level for a 1-year-old child is 135-145 mmol/L, which is the same reference range used across all pediatric age groups and adults. 1
Reference Range
Serum sodium of 135-145 mmol/L is the standard reference range for children of all ages, including 1-year-olds, as established by the American Academy of Pediatrics 1
This range remains consistent from infancy through adulthood, making it straightforward to interpret laboratory values 1
Clinical Context for Abnormal Values
Hypernatremia (Na >145 mmol/L)
Hypernatremia is defined as sodium >145 mmol/L and often results from inadequate water intake or excessive water losses in young children 2
Values >160 mmol/L with altered mental status require PICU admission for intensive monitoring 3
Hyponatremia (Na <135 mmol/L)
Hyponatremia is defined as sodium <135 mmol/L and reflects absolute or relative water overload 2
The severity classification includes: mild (130-134 mmol/L), moderate (125-129 mmol/L), and severe (<125 mmol/L) 4
In young children, hyponatremia can result from excessive free water intake, gastrointestinal losses, or inappropriate fluid management 2
Monitoring Considerations
Daily monitoring of serum sodium is recommended during the initial days of parenteral nutrition or acute illness, then adjusted based on clinical stability 2
Weight changes, urine output, and clinical hydration status should be assessed alongside sodium levels to determine the underlying cause of any abnormality 2