Sodium concentration in serum/plasma
This test measures the amount of sodium, a key mineral, in your blood. Sodium helps regulate fluid balance, nerve and muscle function, and blood pressure.
["Sodium levels help doctors check for dehydration, kidney issues, or conditions like high blood pressure."]
Key facts at a glance
- LOINC
- 87451-1
- Short code
- Sodium Spec-mCnc
- Synonyms
- Sodium Spec-mCnc
- 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?
Your doctor may order this test if you have symptoms like excessive thirst, confusion, swelling, or irregular heartbeat. It’s also used to monitor conditions like heart failure, kidney disease, or certain medications that affect sodium levels.
What to Expect Before the Test
You’ll typically have a small needle inserted into your arm to draw blood. No special preparation is needed, but avoid eating or drinking for a short time before if instructed by your doctor.
What the Results Mean
Results are compared to standard ranges, but exact values can vary by lab. Low sodium (hyponatremia) may cause dizziness or seizures, while high sodium (hypernatremia) can lead to confusion or muscle spasms.
Common Conditions Affecting Sodium Levels
Conditions like kidney problems, heart failure, or excessive sweating (e.g., from heat or exercise) can alter sodium levels. Certain medications, such as diuretics or steroids, 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.
Sodium levels are critical for maintaining fluid balance in the body. Abnormalities can lead to serious complications, such as seizures, heart rhythm issues, or even coma in extreme cases. Regular monitoring is important for patients with chronic conditions like kidney disease or heart failure.
Short name
Sodium Level
Frequently asked questions
What causes sodium levels to be too low?
What causes sodium levels to be too high?
How often should I get this test?
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