What is Sodium?
your fluid balance
Sodium regulates the body's fluid balance and nerve function. The value is kept within narrow limits, and abnormalities usually reflect fluid imbalance.
The value rarely changes because of dietary salt - it reflects the body's water content.
Test facts
- Unit
- mmol/L
- Sample
- Serum
- Fasting
- No fasting needed
- Turnaround
- 1 day
What does low Sodium mean?
Low sodium (hyponatraemia) appears with overhydration, certain medications, heart failure, and hormonal disorders.
What does high Sodium mean?
High sodium (hypernatraemia) most often reflects dehydration.
Panels that measure Sodium
- Deep Baseline
More markers in the same area
Launching in Stockholm in 2026.
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This is general information about the marker, not an assessment of your values and not medical advice. Last updated: May 2026.