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Serum or plasma concentration of sodium measured by ion-selective electrode

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

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

Quick summary

["Sodium levels help doctors diagnose conditions like dehydration, kidney problems, or high blood pressure."]

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

Key facts at a glance

LOINC
105062-4
Short code
S pyo DNA Spec Ql
Synonyms
S pyo DNA Spec Ql
Category
coagulation
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?

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 electrolyte imbalances.

What to Expect Before the Test

You’ll likely have a small needle inserted into your arm or hand to draw blood. No special preparation is needed, but avoid eating or drinking for a few hours before if instructed.

What the Results Mean

Results are compared to standard ranges, but your doctor will interpret them based on your health and symptoms. Very low or high sodium can signal serious issues requiring medical attention.

Common Conditions Affecting Sodium Levels

Low sodium (hyponatremia) may occur from excessive sweating, vomiting, or kidney problems, while high sodium (hypernatremia) can result from dehydration or overuse of salt.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Sodium levels are critical for overall bodily function. Abnormal results may indicate dehydration, kidney dysfunction, heart issues, or hormonal imbalances that need medical evaluation.

Short name

Sodium Level

Frequently asked questions

What causes sodium levels to be too low or too high?
Low sodium can be caused by excessive fluid loss (e.g., diarrhea, sweating), kidney problems, or certain medications. High sodium often results from dehydration, excessive salt intake, or hormonal imbalances like Cushing’s syndrome.
How long does it take to get the results?
Results are typically available within 1–2 business days, depending on your lab’s processing time. Your doctor will contact you with the final report.
Can I eat or drink anything before the test?
Generally, you should avoid food and drink for 4–8 hours before the test unless your doctor specifies otherwise. Follow their instructions to ensure accurate results.
  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