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Sodium Test

✅ Up to date🔬 Evidence: ModerateInternal Medicine
Diğer adları: Na, Serum sodium, Sodium level
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Discuss your test results with your doctor. This page is for informational purposes only and does not provide a diagnosis.

⚡ Key Facts

• Serum sodium reflects the body's water balance — it does not directly measure salt intake • Normal: 136–145 mmol/L • Low sodium (hyponatremia) is one of the most common electrolyte disorders • Critical imbalances may require urgent evaluation

🧪 What Does This Test Measure?

The sodium test measures the concentration of sodium in the blood, the primary electrolyte responsible for maintaining fluid balance and blood pressure.

📋 Why Is It Ordered?

Ordered for fluid-electrolyte balance evaluation, kidney/heart/liver disease monitoring, and medication side effect assessment.

🔧 Preparation

No special preparation is generally required. Measured as part of routine blood panels.

📊 Reference Ranges

Normal: 136–145 mmol/L Hyponatremia: <135 mmol/L Hypernatremia: >145 mmol/L ⚠️ Reference ranges may vary slightly by laboratory.

⬆️ High Values

High sodium (hypernatremia) is usually associated with water loss or insufficient water intake rather than excess salt consumption.

⬇️ Low Values

Low sodium (hyponatremia) is most commonly associated with excess body water. Certain medications, heart failure, and hormonal conditions may contribute.

⚙️ What Can Affect Results?

Fluid intake, medications, kidney function, hormonal conditions, and age may affect sodium results.

🔬 Evidence Summary

Moderate evidence: 2 guidelines and 4 comprehensive reviews.

✅ Key Takeaways

💡

What you learned: Serum sodium reflects water balance rather than salt intake. Both high and low values require clinical evaluation.

⛔

A sodium result alone cannot determine the cause of imbalance. Clinical context, other tests, and fluid assessment are needed.

🔬 Sources Used on This Page

6 sources · Most recent publication: 2023
📋
Guideline
Expert society and guideline recommendations
2
sources
📖
Review
Comprehensive topic evaluation
4
sources
Overall assessment: Evidence level for this topic is moderate. This page is supported by 2 guidelines, 4 reviews.

📝 Questions to Ask Your Doctor

Be prepared for your appointment. Add questions to your list.

Last reviewed: 4/1/2026
Next review: 7/1/2026

🔗 Related Topics

🧪 Potasyum (K)🧪 Klor (Cl)🧪 Creatinine🧪 eGFR
⚖️ This page does not replace medical advice. Make treatment decisions with your doctor.
Content is based on scientific studies indexed in PubMed and current clinical guidelines.