Sodium levels: what's normal, high and low
A key electrolyte that controls fluid balance, blood pressure, and nerve and muscle function.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
Sodium is measured with a standard blood draw after an 8–12 hour fast. A typical reference range is 135 – 145 mmol/L. At TestWell it's $20.99 all-in as Basic Metabolic Panel, results in 1–3 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis.
- Units
- mmol/L / mEq/L
- Sample
- Blood draw
- Fasting
- 8–12 hours
- Results
- 1–3 business days
- Price
- $20.99
- Labs
- Quest or Labcorp · BioReference in NY/NJ
Sodium Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 135 – 145 mmol/L |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
What your Sodium result may mean
Often reflects dehydration or excess salt intake.
What a high Sodium means: causes, symptoms, next steps →Can reflect overhydration, certain medications (especially diuretics), or hormonal conditions.
What a low Sodium means: causes, symptoms, next steps →Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
How do you get a Sodium test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. Sodium is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Basic Metabolic Panel | This marker only | $20.99 |
Quest vs. Labcorp for Sodium: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $20.99 |
| Labcorp | Yes | $21.99 |
| BioReference (NY & NJ) | Yes | $22.99 |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Frequently asked
Often reflects dehydration or excess salt intake. A single result above the reference range is a prompt to look closer with a clinician — often a repeat test and related markers — not a diagnosis on its own.
Ready to test your sodium?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $20.99.