Metabolic
Sodium
LOINC 2951-2 · mEq/L
Ranges
Reference range: 135–145 mEq/L
What it is
Sodium is an electrolyte that controls the balance of water in and around your cells, and supports nerve and muscle function.
Why it matters
It is central to hydration and fluid balance, and abnormal levels can affect the brain and overall function.
What high values can mean
A higher value usually reflects dehydration or too little water relative to sodium.
What low values can mean
A lower value (hyponatremia) can follow excess fluid, certain medications or hormonal causes and may cause confusion if severe.
How to improve it
Sodium is balanced by the body's water regulation; care addresses hydration and the underlying cause.
Food & lifestyle
For most people the issue is fluid balance, not salt intake; very high salt diets are best moderated for heart health.
Preparing for the test
Often part of a metabolic panel; fasting is not specifically required — follow your lab.
When to talk to a doctor
Discuss an abnormal sodium with a doctor, especially with confusion, severe headache or marked thirst.
Related markers
Sources
- MedlinePlus (NIH)
- Testing.com (AACC)
Content reviewed on June 26, 2026
Medical disclaimer
This content is for educational purposes only. It is not medical advice and does not diagnose, treat, or prevent any condition. Reference ranges vary between laboratories — always use the range printed on your report and discuss your results with a healthcare professional.
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