Sodium concentration in blood (serum/plasma)
This test measures the amount of sodium, a key mineral, in your blood. Sodium helps balance fluids and maintain proper heart and muscle function.
["Your sodium level helps doctors check if you have too much or too little sodium in your body."]
Key facts at a glance
- LOINC
- 2947-0
- Short code
- Sodium Bld-sCnc
- Synonyms
- Sodium Bld-sCnc
- Category
- electrolyte
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Ref low
- 136
- Ref high
- 145
- Critical range
- 120 N/A – 160 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84295
- SNOMED
- 110741000
- Specimen volume
- 3 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Doctors may order this test to diagnose or monitor conditions like dehydration, kidney problems, heart disease, or certain hormonal imbalances. It can also help identify signs of high blood pressure or fluid retention.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm to draw blood. If you’re on a low-sodium diet, your doctor may ask you to stop temporarily.
What Happens During the Test?
A healthcare professional will clean your arm and insert a needle to collect blood. The sample is then sent to a lab for testing sodium concentration.
What Are Possible Results?
Results are usually reported as a numerical value (e.g., mmol/L), but your doctor will interpret them based on your health and symptoms. Abnormally high or low sodium can cause serious health issues.
Reference range
Adult: 136-145 mmol/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Sodium is vital for nerve and muscle function, fluid balance, and blood pressure regulation. Too much sodium (hypernatremia) can lead to confusion, seizures, or kidney damage, while too little (hyponatremia) may cause nausea, weakness, or irregular heartbeat. Your doctor will use these results to guide treatment, such as adjusting medications or fluid intake.
Short name
Sodium Level (Serum/Plasma)
Frequently asked questions
What causes sodium levels to be too high?
What causes sodium levels to be too low?
Yes, your diet can influence sodium levels. High-sodium foods (like processed snacks or salty meals) may raise sodium, while low-sodium diets may lower it. Your doctor may ask you to avoid extreme dietary changes before testing.
Sources
- 1
- 2Lab Tests OnlineSource
- 3
Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy