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Sodium concentration in serum/plasma (quantitative measurement)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of sodium in your blood, which helps your body maintain proper fluid balance and nerve function.

Quick summary

Sodium levels are critical for heart health, muscle function, and preventing fluid imbalances.

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
72069-8
Short code
SODIUM-PROFILINGMODELING-PRESCRIBED-FOR-ANY-DIALYSIS-SESSIONS-IN-THE-REPORTING
Synonyms
—
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
Method
esrd
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 to check for conditions like high blood pressure, kidney problems, dehydration, or heart issues. It’s also used to monitor sodium levels in people on dialysis or those with certain dietary restrictions.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for a few hours before the blood draw if your lab uses a fasting protocol. Bring any medications you’re taking to your appointment.

How the Test Is Performed

A healthcare provider will draw blood from a vein in your arm using a small needle. You may feel a slight sting, but it usually doesn’t cause pain. The blood sample is sent to a lab for analysis.

What the Results Mean

Results are compared to standard ranges for your age and health status. Low sodium (hyponatremia) can cause headaches or confusion, while high sodium (hypernatremia) may lead to muscle cramps or irregular heartbeat. Your doctor will discuss your specific results with you.

Reference range

Adult: 136-145 mmol/LN/A

Specimen: serum

No special preparation required. Stay well hydrated.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Sodium Level

Frequently asked questions

What causes sodium levels to change?
Sodium levels can be affected by diet (too much salt), kidney function, vomiting, diarrhea, or certain medications. Chronic conditions like heart failure or liver disease may also influence sodium balance.
How often should I get this test?
Your doctor will determine how often you need this test based on your health condition. For example, people on dialysis may need sodium checks regularly to adjust their treatment.
Can I adjust my sodium intake based on my test results?
Yes, but only under medical supervision. If your sodium is too high or too low, your doctor may recommend dietary changes, medications, or other treatments to restore balance.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

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.

Medical Disclaimer

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