Sodium, Urine (Substance Concentration)
This test measures the concentration of sodium in a urine sample. It can help assess how the kidneys are handling sodium and fluid balance, especially when symptoms suggest dehydration, swelling, or changes in blood pressure.
["Urine sodium can provide information about kidney sodium handling and fluid balance, but results must be interpreted alongside the collection method and other clinical findings."]
Key facts at a glance
- LOINC
- 2955-3
- Short code
- Sodium Ur-sCnc
- Synonyms
- Sodium Ur-sCnc
- Category
- electrolyte
- Sample
- urine
- Container
- Sterile urine container
- 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
- CPT
- 84295
- SNOMED
- 110741000
- Specimen volume
- 10 mL
- Stability
- Room temperature: 2h, Refrigerated: 24h, Frozen: 7d
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
The test reports the amount of sodium present in a measured volume of urine. Higher or lower concentrations can reflect changes in fluid intake, kidney function, medications, or hormone-related regulation of sodium and water balance.
How the Test Is Collected
Urine may be collected as a single specimen or over a specified period, depending on the test ordered. A timed collection can better show how much sodium the body is excreting, while a random sample mainly reflects sodium concentration at one point in time.
Why It May Be Ordered
Clinicians may order urine sodium when evaluating dehydration, edema, hypertension, low blood pressure, or suspected abnormalities in kidney or adrenal function. It may also be used to monitor certain medicines that affect sodium and fluid balance.
Factors That Can Affect the Result
Dietary sodium, fluid intake, exercise, illness, kidney function, and medications such as diuretics can all influence urine sodium. The time of collection and whether the sample was collected over a full day also affect interpretation.
Reference range
Adult: 136-145 mmol/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Urine sodium is interpreted together with blood sodium, urine volume, kidney function tests, and the clinical situation. An abnormal result may indicate excess sodium loss, impaired kidney handling, or excess sodium retention, but it does not identify a specific condition by itself.
Short name
Urine sodium
Frequently asked questions
Does a urine sodium result diagnose a specific condition?
Why does the collection method matter?
Can medicines affect urine sodium?
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