Sodium and Creatinine, Urine and Stool
Measures sodium and creatinine in urine and stool to help assess fluid and electrolyte balance, intestinal losses, and kidney function.
["These results are interpreted together with symptoms and other tests to evaluate fluid balance and possible sodium loss."]
Key facts at a glance
- LOINC
- 33951-5
- Short code
- Sodium/Creat Ur-sRto
- Synonyms
- Sodium/Creat Ur-sRto
- 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?
This test measures the amount of sodium, an electrolyte, and creatinine, a waste product from muscle, in urine and stool. The results may be used to evaluate how the body handles fluid, sodium, and kidney filtration.
Why might I need this test?
A clinician may order these measurements when investigating dehydration, diarrhea, unusual fluid loss, or changes in kidney function. Stool sodium can help estimate sodium lost through the bowel, while creatinine measurements provide information about urine concentration and muscle-related metabolism.
How is the test performed?
Urine and stool samples are collected as directed and analyzed in the laboratory. The type of urine collection, such as a single specimen or a timed collection, depends on the specific order and clinical question.
How do I prepare for the test?
Follow the laboratory's collection instructions carefully, including any timing requirements and the containers provided. Tell the healthcare team about medicines such as diuretics and about major changes in fluid intake, but do not stop medicines unless instructed.
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.
Low urine sodium or elevated urine creatinine may occur with dehydration or reduced kidney blood flow, although interpretation depends on the clinical situation. High stool sodium may indicate increased intestinal sodium loss, such as during some forms of diarrhea. Results should be interpreted together with symptoms, examination findings, and other laboratory tests because diet, medicines, kidney function, and fluid intake can affect them.
Short name
Urine and Stool Sodium and Creatinine
Frequently asked questions
Why are sodium and creatinine measured together?
What does an abnormal stool sodium result mean?
Do I need to change 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 16, 2026. · Read our editorial policy