Serum Sodium (Electrolyte Measurement)
This test measures the amount of sodium, a key mineral electrolyte, in your blood serum. Sodium helps regulate fluid balance and nerve function.
["Sodium levels help assess hydration and kidney function."]
Key facts at a glance
- LOINC
- 54453-6
- Short code
- Smn Analysis method
- Synonyms
- Smn Analysis method
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 86038
- 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 to check for dehydration, kidney problems, or conditions affecting fluid balance, such as heart failure or certain hormonal disorders. It can also be part of a routine check-up or monitoring for conditions like high blood pressure or metabolic disorders.
What to Expect Before the Test
No special preparation is needed for this test. You may have a small needle inserted into your arm to draw blood. If you’re on a low-sodium diet or have certain medications, let your healthcare provider know before the test.
What Happens During the Test?
Blood is collected from a vein in your arm. The process usually takes a few minutes. You may feel a slight pinch, but it’s generally quick and painless. The blood sample is then sent to a lab for analysis.
What Are Common Results and Their Meanings?
Results are typically reported in millimoles per liter (mmol/L). While reference ranges vary by lab, low sodium levels (hyponatremia) may indicate overhydration or kidney issues, while high levels (hypernatremia) could signal dehydration or kidney problems. Your doctor will interpret results in the context of your overall health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Abnormal sodium levels can cause serious health issues, such as confusion, seizures, or even coma in extreme cases. Low sodium may lead to swelling, muscle cramps, or irregular heartbeat, while high sodium can cause thirst, nausea, or rapid heartbeat. Regular monitoring helps manage conditions like heart failure, liver disease, or certain medications that affect sodium balance.
Short name
Serum Sodium
Frequently asked questions
What causes low sodium levels?
What causes high sodium levels?
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