Sodium concentration in serum/plasma
This test measures the amount of sodium, a key electrolyte, in your blood. Sodium helps regulate fluid balance and nerve function.
["Your sodium levels help doctors check for dehydration, kidney issues, or other health concerns."]
Key facts at a glance
- LOINC
- 39787-7
- Short code
- Sodium DiafP-sCnc
- Synonyms
- Sodium DiafP-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 Sodium Levels Matter
Sodium is essential for maintaining proper fluid balance in your body. Too little or too much sodium can lead to serious health problems, such as swelling, high blood pressure, or even seizures in extreme cases.
What Can Affect Sodium Levels?
Several factors can influence your sodium levels, including diet (especially salt intake), kidney function, dehydration, or certain medications. If you’re experiencing symptoms like excessive thirst, swelling, or confusion, let your doctor know.
Common Causes of Abnormal Results
Low sodium levels (hyponatremia) may occur due to excessive sweating, vomiting, diarrhea, or kidney problems. High sodium levels (hypernatremia) can result from dehydration, excessive salt intake, or conditions like diabetes insipidus.
What to Expect During the Test
This test is usually done by drawing a small amount of blood from your arm. The sample is sent to a lab for analysis. Results are typically ready within a few days.
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 levels are critical for diagnosing conditions like heart failure, kidney disease, or electrolyte imbalances. Your doctor may order this test if you have symptoms of fluid or electrolyte issues, or if they suspect a medical condition requiring sodium management.
Short name
Serum Sodium
Frequently asked questions
How often should I get this test?
What are the normal ranges for sodium?
Can diet changes affect sodium test results?
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