Urine Sodium-to-Creatinine Ratio
Measures sodium and creatinine in urine to estimate sodium excretion relative to urine concentration, helping assess salt intake and kidney sodium handling.
["This urine test helps show whether the kidneys are excreting more or less sodium than expected."]
Key facts at a glance
- LOINC
- 43223-7
- Short code
- Sodium/Creat Ur-Rto
- Synonyms
- Sodium/Creat Ur-Rto
- Category
- kidney
- 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
What is this test?
A urine sodium-to-creatinine ratio measures the amount of sodium in urine relative to creatinine, a muscle breakdown product. Creatinine acts as a rough adjustment for urine concentration, so the ratio can help estimate sodium excretion.
Why might I need this test?
This test may be used to assess dietary sodium intake, monitor blood pressure or fluid-related conditions, and evaluate how the kidneys handle sodium. It may also be used in children when estimating salt intake.
How is the test performed?
A urine sample is collected as directed by your clinician. The laboratory measures sodium and creatinine in the sample and calculates the sodium-to-creatinine ratio. The collection may be a single urine sample or a timed collection, depending on the order.
How do I prepare for the test?
Follow the collection instructions provided by your clinician. If a timed collection is required, collect all urine for the specified period and record the start and finish times. Otherwise, no special preparation is generally needed.
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.
A higher ratio may reflect greater sodium excretion, higher salt intake, reduced kidney sodium retention, or conditions affecting fluid balance. A lower ratio may occur with low sodium intake, dehydration, increased fluid retention, or reduced sodium excretion. Results are interpreted with kidney function, hydration, age, urine collection method, and other clinical findings.
Short name
Urine Na/Cr Ratio
Frequently asked questions
Does this test measure blood sodium?
Why is creatinine included in the result?
What can affect the urine sodium-to-creatinine ratio?
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