24-Hour Urinary Sodium and Chloride Ratio (with Creatinine)
This test measures the balance of sodium and chloride in your urine over 24 hours, along with a small sample of creatinine, to help assess kidney function and electrolyte balance.
["Helps evaluate kidney health and fluid/electrolyte balance over a full day’s urine output."]
Key facts at a glance
- LOINC
- 23918-6
- Short code
- OF .60% NaCl 24h Inc NFr RBC
- Synonyms
- OF .60% 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 conditions like kidney disease, fluid imbalances, or certain metabolic disorders. It can also help monitor long-term kidney function or diagnose issues related to excessive sodium or chloride retention.
What to Expect Before the Test
You’ll need to collect all urine for 24 hours, starting and ending with a void. A small blood or urine sample for creatinine may be taken at the same time. Follow your doctor’s instructions carefully to ensure accurate results.
How the Test Works
Your urine is collected in a container over 24 hours, and the sodium, chloride, and creatinine levels are measured. The ratio helps determine how well your kidneys filter these substances from your blood.
What the Results Mean
Abnormal ratios may indicate problems like kidney dysfunction, excessive sodium loss (e.g., from diuretics), or fluid retention. Your doctor will interpret results in the context of your overall health and symptoms.
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.
This test is particularly useful for diagnosing or monitoring conditions such as nephrotic syndrome, certain kidney diseases, or electrolyte imbalances. It can also help assess how well medications (like diuretics) are affecting fluid and electrolyte levels in your body.
Short name
24h Na:Cl:Creatinine Ratio
Frequently asked questions
What causes abnormal results?
How long will I need to collect urine for this test?
Can I take medications while collecting urine for 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