24-Hour Urine Potassium and Creatinine (Potassium-to-Creatinine Ratio)
Measures potassium and creatinine in urine collected for 24 hours to assess potassium excretion and help evaluate kidney function and collection adequacy.
["This test helps determine how much potassium your body is losing in urine and whether a 24-hour collection appears complete."]
Key facts at a glance
- LOINC
- 13798-4
- Short code
- Potassium/Creat 24h Ur
- Synonyms
- Potassium/Creat 24h Ur
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Ref low
- 3.5
- Ref high
- 5
- Critical range
- 2.5 N/A – 6.5 N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 84132
- SNOMED
- 110742001
- 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 potassium and creatinine in a 24-hour urine collection. Creatinine is used to help assess whether the collection is complete, and the results may be used to calculate a potassium-to-creatinine ratio.
Why might I need this test?
It may be ordered to evaluate potassium balance, investigate low or high blood potassium levels, or assess how the kidneys are handling potassium. It can also help monitor the effects of medications or certain conditions that change potassium excretion.
How is the test performed?
All urine produced over a full 24-hour period is collected in a labeled container and sent to a laboratory for measurement. The laboratory reports the urine amounts and may calculate a potassium-to-creatinine ratio.
How do I prepare for the test?
Follow the collection instructions provided by the laboratory, including the exact starting and ending times. Maintain your usual diet and fluid intake unless your clinician instructs you to change them, and tell the laboratory about any relevant medications or supplements.
Reference range
Adult: 3.5-5.0 mmol/LN/A
No special preparation required. Stay well hydrated.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Higher urine potassium may reflect increased potassium intake, medication effects, or reduced kidney reabsorption. Lower urine potassium may occur with low intake, vomiting, certain medications, or increased kidney reabsorption. Creatinine helps assess the completeness of the collection, while the potassium-to-creatinine ratio can help interpret potassium excretion in relation to urine concentration.
Short name
24-Hour Urine Potassium/Creatinine
Frequently asked questions
Why is a 24-hour urine collection needed?
What if I miss part of the collection?
Do I need to stop medications or supplements?
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