Sodium and Potassium, 24-Hour Urine
This test measures the amounts of sodium and potassium eliminated in urine over a 24-hour period. It may also help assess sodium and potassium balance and kidney function when interpreted with other clinical information.
["The results show how much sodium and potassium your body is losing in urine and can help clinicians evaluate fluid and electrolyte balance."]
Key facts at a glance
- LOINC
- 44406-7
- Short code
- Sodium/Potassium 24h Ur-sRto
- Synonyms
- Sodium/Potassium 24h Ur-sRto
- Category
- electrolyte
- 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 the Test?
A 24-hour urine test collects all urine produced over one full day. The collection is usually started after emptying the bladder and ended at the same time the following day, with the time and any missed samples recorded.
What Does It Measure?
Sodium is an important electrolyte involved in fluid balance, blood pressure, and nerve and muscle function. Potassium is also an electrolyte needed for normal heart and muscle function. Measuring both in urine can help evaluate how the kidneys handle these minerals.
How Is the Collection Completed?
Collect urine in the container provided by the laboratory and keep it refrigerated if instructed. Avoid combining urine from another collection period, and tell the healthcare team if the collection was incomplete or a sample was spilled.
Why Might This Test Be Ordered?
Clinicians may order it when evaluating hypertension, swelling, kidney conditions, or unusual changes in fluid balance. It may also help monitor certain medicines or dietary changes that affect sodium and potassium levels.
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.
Abnormal results can reflect changes in kidney function, fluid status, dietary intake, medications, or other health conditions. Results should be interpreted alongside blood tests, symptoms, medical history, and the completeness of the 24-hour collection; an abnormal value alone does not establish a diagnosis.
Short name
24-Hour Urine Sodium and Potassium
Frequently asked questions
Is a 24-hour urine collection different from a routine urine test?
What can affect the results?
Do I need to change my diet or medications before the 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