Sodium
Sodium is the primary extracellular electrolyte, maintaining fluid balance, blood pressure, and nerve/muscle function. The kidneys precisely regulate sodium through the renin-angiotensin-aldosterone system (RAAS) and ADH (antidiuretic hormone). Normal serum sodium reflects water balance more than sodium intake.
Why it matters: Low sodium (hyponatremia) is the most common electrolyte disturbance in hospital settings. Milder cases are associated with nausea and confusion; severe cases with more serious effects. High sodium (hypernatremia) reflects water deficit and can be associated with altered mental status.
May increase with:
May decrease with:
What is Sodium?
Sodium is the primary extracellular electrolyte, maintaining fluid balance, blood pressure, and nerve/muscle function. The kidneys precisely regulate sodium through the renin-angiotensin-aldosterone system (RAAS) and ADH (antidiuretic hormone). Normal serum sodium reflects water balance more than sodium intake.
What might a high or low Sodium mean?
Low sodium (hyponatremia) is the most common electrolyte disturbance in hospital settings. Milder cases are associated with nausea and confusion; severe cases with more serious effects. High sodium (hypernatremia) reflects water deficit and can be associated with altered mental status.
What is the typical reference range for Sodium?
The general-population reference range shown here is 136 – 145 mmol/L. Reference ranges describe the general population and are not a personal target — discuss your results with your physician.
What can affect Sodium?
It may be higher with: Dehydration (water loss exceeds sodium loss), Diabetes insipidus, Excessive sodium intake (rare cause), Cushing's syndrome, Hyperaldosteronism. It may be lower with: SIADH (excessive ADH secretion), Diuretics (especially thiazides), Heart failure, Cirrhosis with ascites, Excessive water intake (water intoxication), Hypothyroidism, Adrenal insufficiency.