24-Hour Urinary Sodium and Chloride Ratio (Mass Concentration)
This test measures the balance of sodium and chloride in your urine over 24 hours. It helps assess how well your kidneys are regulating these minerals, which can indicate kidney function or potential electrolyte imbalances.
["This test helps doctors check if your kidneys are working properly or if you have conditions affecting sodium and chloride levels."]
Key facts at a glance
- LOINC
- 23921-0
- Short code
- OF .75% NaCl 24h Inc NFr RBC
- Synonyms
- OF .75% NaCl 24h Inc NFr RBC
- Category
- electrolyte
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Ref low
- 4.2
- Ref high
- 5.9
- Critical range
- 2 N/A – 7 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 85041
- SNOMED
- 900000000000003001
- 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 kidney disease, high blood pressure, or other conditions that affect how your body handles sodium and chloride. It can also help diagnose or monitor conditions like kidney stones, heart failure, or certain metabolic disorders.
What to Expect Before the Test
You’ll need to collect all your urine for 24 hours, starting and ending at the same time each day. Drink plenty of fluids but avoid adding extra salt to your diet during this period. Your doctor or lab technician will provide detailed instructions to ensure accurate results.
What the Test Results Mean
The test compares the amounts of sodium and chloride in your urine. Abnormal results may suggest issues with kidney function, fluid balance, or how your body processes these minerals. Your doctor will interpret the results in relation to your overall health and symptoms.
Common Conditions This Test Helps Diagnose
This test can help identify kidney diseases, such as chronic kidney disease or nephrotic syndrome, as well as conditions like primary hyperaldosteronism (a hormone disorder), heart failure, or certain types of kidney stones.
Reference range
Adult males: 4.2-5.9; Females: 3.8-5.1 x 10^12/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Understanding the Role of Sodium and Chloride
Short name
24h Urine Na/Cl Ratio
Frequently asked questions
How is urine collected for this test?
What are typical reference ranges for this test?
Can I take medications or eat certain foods before 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 17, 2026. · Read our editorial policy