Urine Creatinine-to-Creatinine Clearance Ratio (24-hour urine collection)
This test measures how well your kidneys filter waste products from your blood over a full day, using urine and blood samples. It helps assess kidney function and fluid balance.
["Helps diagnose kidney issues and check how well your kidneys are working over time."]
Key facts at a glance
- LOINC
- 81603-3
- Short code
- NM Vs bld flow+kid fn W diur IV+RNC IV
- Synonyms
- NM Vs bld flow+kid fn W diur IV+RNC IV
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- nm
- 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 kidney problems, such as chronic kidney disease, fluid imbalance, or other conditions affecting how your kidneys filter waste. It’s also used to monitor kidney function in people with diabetes, high blood pressure, or other long-term health conditions.
How the Test Works
You’ll collect all your urine for a full 24-hour period in a clean container. At the start and end of the collection, your doctor or lab technician will take a blood sample to measure creatinine levels. The urine and blood samples are then sent to a lab to calculate your kidney’s filtering ability.
What to Expect Before the Test
No special preparation is needed, but you should drink enough water to produce clear urine. Avoid taking certain medications (like some diuretics) that could affect kidney function unless approved by your doctor.
What to Expect During the Test
You’ll collect urine in a container for 24 hours, changing it every time you urinate. A simple blood draw will be done at the start or end of the collection period.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test helps identify kidney dysfunction by comparing how much creatinine (a waste product) is in your urine versus your blood. Low or high ratios may signal problems like kidney disease, dehydration, or fluid overload. It’s especially useful for monitoring chronic conditions that affect kidney function.
Short name
24-Hour Urine Creatinine Clearance
Frequently asked questions
How long does the urine collection last?
What should I do if I miss any urine during the collection?
Can I drink alcohol or certain medications during the urine collection?
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