Sodium concentration in urine
This test measures how much sodium (a key mineral) is present in your urine, helping assess kidney function and fluid balance.
["Helps evaluate kidney health and electrolyte balance in urine."]
Key facts at a glance
- LOINC
- 35678-2
- Short code
- Sodium ?Tm Ur-sCnc
- Synonyms
- Sodium ?Tm 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
Why Is This Test Done?
Your healthcare provider may order this test to check if your kidneys are properly filtering sodium, which can help diagnose conditions like kidney disease, dehydration, or excessive fluid retention. It may also be used to monitor long-term health in people with certain chronic conditions.
What to Expect Before the Test
No special preparation is needed. You’ll provide a urine sample, typically collected over a 24-hour period or a random sample. If it’s a 24-hour urine test, you’ll need to collect all urine for a full day, including any you wake up with.
What the Results Mean
Results help determine if your kidneys are retaining or losing sodium too much. Abnormal levels might suggest kidney problems, fluid imbalances, or other health concerns that need further evaluation.
Common Conditions Monitored
This test is often used to monitor kidney function, especially in people with hypertension, diabetes, or chronic kidney disease. It can also help assess conditions like congestive heart failure or certain electrolyte disorders.
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.
Sodium in urine is closely tied to kidney function and overall fluid balance. High levels may indicate kidney issues or excessive sodium loss, while low levels could signal kidney problems or fluid overload. Your provider will interpret results in the context of your health and other tests.
Short name
Urine Sodium
Frequently asked questions
What causes high urine sodium levels?
What causes low urine sodium levels?
Does diet affect urine sodium levels?
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