Serum or plasma sodium concentration (mass concentration)
This test measures the amount of sodium in your blood, which helps your body maintain proper fluid balance, nerve function, and muscle contractions.
["Sodium levels help doctors check for dehydration, electrolyte imbalances, or conditions like high blood pressure or kidney problems."]
Key facts at a glance
- LOINC
- 60042-9
- Short code
- NAPA Bld-mCnc
- Synonyms
- NAPA Bld-mCnc
- Category
- chemistry
- Sample
- whole-blood
- Container
- Lavender-top (EDTA)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 Sodium Levels Matter
Sodium is a key mineral that helps regulate how much fluid is in and out of your cells. Too little or too much can cause serious health issues, like swelling, muscle cramps, or even heart problems. Your doctor may order this test if you have symptoms like excessive thirst, confusion, or unexplained weight changes.
What to Expect Before the Test
You may have this test done by drawing blood from a vein in your arm. No special preparation is usually needed, but tell your doctor about any medications you’re taking, especially those that affect sodium levels (like diuretics or salt tablets).
What the Results Mean
Results are compared to a standard range for healthy adults. Low sodium (hyponatremia) can cause headaches or fatigue, while high sodium (hypernatremia) may lead to dry mouth or rapid heartbeat. Your doctor will discuss your specific results with you.
Common Causes of Abnormal Results
Sodium levels can drop from excessive sweating, vomiting, or kidney issues, while high levels may result from dehydration, heart problems, or overuse of salt. Chronic conditions like heart failure or liver disease can also affect sodium balance.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal sodium levels are often an early warning sign of underlying health issues. For example, dangerously low sodium can impair brain function, while dangerously high sodium may stress your heart. Regular monitoring is especially important for people with kidney disease, heart failure, or those on certain medications.
Short name
Sodium level
Frequently asked questions
How often should I get this test?
What happens if my sodium level is too low or too high?
Can I eat or drink anything before 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