Sodium is a vital electrolyte that regulates fluid balance, blood pressure, and nerve/muscle function.

The 24-hour urine test provides a more accurate measure of sodium excretion compared to a single random urine sample.

Clinical uses include:

Assessing kidney function and sodium handling.

Investigating causes of hyponatremia (low sodium) or hypernatremia (high sodium).

Monitoring patients with hypertension, heart failure, adrenal disorders, or diuretic therapy.

Evaluating dietary sodium intake and excretion balance.

The test requires collecting all urine passed in 24 hours in a special container.

Analyte: Sodium concentration in 24-hour urine.

Normal Range: Approximately 40–220 mmol/24 hrs (varies by lab and diet).

High Sodium Excretion: May indicate excessive dietary intake, diuretic use, renal tubular disorders, or hyperaldosteronism.

Low Sodium Excretion: May suggest poor intake, dehydration, chronic kidney disease, adrenal insufficiency, or hyponatremia due to non-renal causes.

Clinical Use:

Detects abnormalities in sodium metabolism.

Differentiates renal vs non-renal causes of sodium imbalance.

Supports diagnosis of endocrine, cardiovascular, and renal disorders.