Sodium concentration in serum/plasma
This test measures the amount of sodium, a key mineral electrolyte, in your blood. Sodium helps balance fluids and maintain normal blood pressure and nerve/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
- 17796-4
- Short code
- Sodium Hyperal Soln-sCnc
- Synonyms
- Sodium Hyperal Soln-sCnc
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- 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
- 5 mL
- Stability
- Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why Is This Test Done?
Doctors order sodium tests to diagnose or monitor conditions like dehydration, kidney problems, heart disease, or certain hormonal imbalances. It may also be checked if you’re experiencing symptoms like excessive thirst, confusion, or unexplained weight changes.
What to Expect Before the Test
No special preparation is needed. You’ll have a small needle inserted into your arm or hand to draw blood. If you’re on a sodium-restricted diet, let your doctor know before the test.
What the Results Mean
Results are compared to a standard range, but exact values can vary by lab. Low sodium (hyponatremia) may cause headaches or dizziness, while very high sodium (hypernatremia) could lead to confusion or muscle problems. Your doctor will discuss your specific results with you.
Common Conditions Affecting Sodium Levels
Conditions like kidney disease, heart failure, or excessive sweating can alter sodium levels. Certain medications (e.g., diuretics) or illnesses (e.g., vomiting/diarrhea) may also impact it.
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.
Clinical Significance: Sodium is vital for fluid balance, nerve function, and muscle contractions. Abnormal levels can indicate serious health issues, such as electrolyte imbalances, dehydration, or kidney dysfunction, requiring prompt medical attention.
Short name
Sodium Level
Frequently asked questions
What causes low sodium levels (hyponatremia)?
What causes high sodium levels (hypernatremia)?
Can sodium levels change quickly?
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