24-Hour Urinary Sodium and Chloride Ratio (with Potassium)
This test measures the balance of sodium, chloride, and potassium in your urine over 24 hours to help assess kidney function and electrolyte balance.
["Understanding how your body excretes key minerals over a full day can reveal kidney health and fluid regulation issues."]
Key facts at a glance
- LOINC
- 31105-0
- Short code
- OF .55% NaCl 24h Inc NFr RBC
- Synonyms
- OF .55% 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 you have symptoms like frequent urination, swelling, high blood pressure, or signs of kidney problems. It can also help diagnose conditions like kidney disease, electrolyte imbalances, or certain metabolic disorders.
What to Expect Before the Test
You’ll need to collect all urine for 24 hours, starting and ending with your first morning urine. Store the sample in a refrigerator and return it to the lab on time. Follow your doctor’s instructions carefully to ensure accurate results.
How the Test Works
The test involves measuring the amounts of sodium, chloride, and potassium in your urine over a full day. These minerals help regulate blood pressure, fluid balance, and nerve/muscle function. The ratio helps identify whether your kidneys are properly filtering these substances.
What the Results Mean
Results show the average concentration of sodium, chloride, and potassium in your urine. High or low ratios may indicate kidney issues, fluid retention, or conditions like hyperaldosteronism or diabetes.
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.
Abnormal results can signal kidney dysfunction, electrolyte disorders, or systemic conditions affecting fluid balance. For example, elevated sodium/chloride ratios may suggest kidney failure or excessive sodium intake, while imbalances in potassium could point to metabolic acidosis or kidney stones. Always discuss results with your healthcare provider.
Short name
24h Urine Na:Cl:K Ratio
Frequently asked questions
What causes abnormal results in this test?
How long does it take to get results?
Can I adjust my diet 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