Sodium
Disclaimer: Information on this page is for educational purposes. Consult a physician to interpret your test results. Health Vault helps track biomarker trends but does not replace medical advice.
What This Test Measures
Sodium is the main extracellular cation regulating osmolality and fluid balance. Changes reflect water balance more than total sodium.
Hyponatremia may be dilutional (SIADH, heart failure) or depletional (diuretics, losses).
Hypernatremia usually indicates water deficit (dehydration, diabetes insipidus).
Normal Ranges
| Group | Reference Range |
|---|---|
| Men | 136–145 mmol/L |
| Women | 136–145 mmol/L |
| Children | 135–145 mmol/L |
Reference ranges may vary by laboratory and assay method.
Causes of High Levels
- Dehydration
- Diabetes insipidus
- Hypertonic saline
- Excess salt intake
Causes of Low Levels
- SIADH
- Heart failure
- Cirrhosis
- Diuretics
- Adrenal insufficiency
Test Preparation
- No special preparation
- Report fluid intake and diuretics
Related Biomarkers
| Biomarker | Relationship |
|---|---|
| Potassium | Electrolyte panel |
| Creatinine | Renal concentration |
| Albumin | Osmotic balance |
FAQ
How often should I take this test?
With heart failure/diuretics — every 3–6 months.
What should I do if my result is abnormal?
Acute hyponatremia with confusion/seizures — emergency; chronic — gradual correction under supervision.
Last updated: June 2026