24-Hour Sodium Urine Collection (Quantitative)
This test measures the total amount of sodium (a key electrolyte) excreted in your urine over a full day. It helps assess how well your kidneys are regulating sodium balance, which is important for blood pressure and fluid balance.
["Helps evaluate kidney function and sodium balance over time."]
Key facts at a glance
- LOINC
- 92572-7
- Short code
- Sodium 24h sub Dial fld Qn
- Synonyms
- Sodium 24h sub Dial fld Qn
- 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
- 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 This Test Is Done
Your doctor may order this test if they suspect conditions like kidney disease, excessive sweating, or improper hormone function (such as aldosterone or antidiuretic hormone imbalances) that could affect sodium levels. It’s also used to monitor long-term sodium excretion in certain chronic conditions.
How the Test Works
You’ll collect all urine for a 24-hour period, typically starting after waking up the first morning. The urine is combined and tested for sodium concentration. This provides a full-day picture of sodium loss, unlike a single urine sample.
Sample Collection Tips
To ensure accurate results, collect every drop of urine for 24 hours, including the first morning urine. Store the sample at room temperature and bring it to the lab on time. Follow your healthcare provider’s specific instructions for timing and handling.
What to Expect Before the Test
No special preparation is usually needed, but avoid certain medications (like diuretics) that could affect sodium levels unless instructed otherwise. Drink enough water to maintain normal urine flow but avoid excessive intake.
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.
◆Associated findings1
Short name
24-hour urine sodium
Frequently asked questions
What does a high sodium urine result mean?
What does a low sodium urine result mean?
Can diet affect 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