Serum or plasma sodium concentration (qualitative screening)
This test measures the amount of sodium in your blood, which helps your body maintain proper fluid balance and nerve function.
["Sodium levels can affect hydration, blood pressure, and overall health—keep an eye on them if you have kidney issues or heart conditions."]
Key facts at a glance
- LOINC
- 101679-9
- Short code
- NTS Spec
- Synonyms
- NTS Spec
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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 may order this test to check for dehydration, high blood pressure, kidney problems, or conditions like congestive heart failure. It can also help monitor long-term health if you have a history of sodium-related issues.
What Does a Low or High Sodium Level Mean?
Too little sodium (hyponatremia) can cause headaches, confusion, or muscle cramps. Too much sodium (hypernatremia) may lead to dry mouth, rapid heartbeat, or even seizures in severe cases. Your doctor will interpret results based on your symptoms and overall health.
How Is This Test Performed?
A small blood sample is taken from your arm, and the sodium level is measured using an automated lab test. No special preparation is needed unless instructed otherwise.
What Are Common Causes?
Low sodium can result from excessive sweating, vomiting, diarrhea, or certain medications. High sodium may come from too much salt in your diet or kidney problems that fail to regulate sodium properly.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for diagnosing and managing conditions like **hyponatremia** (dangerously low sodium) or **hypernatremia** (dangerously high sodium), which can affect brain function, muscle control, and blood pressure. It’s also used in monitoring patients with chronic kidney disease, heart failure, or liver disease, where sodium balance is especially important. Early detection helps prevent complications like seizures, confusion, or even coma.
Frequently asked questions
What if my sodium level is out of range?
Does diet affect sodium test results?
Can I take this test at home?
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