Urinary Creatinine-to-Creatinine Clearance Rate (24-hour urine collection)
This test measures how well your kidneys filter waste from your blood over a 24-hour period by analyzing urine and blood creatinine levels.
["Assesses kidney function by comparing urine and blood creatinine levels over a full day."]
Key facts at a glance
- LOINC
- 40662-9
- Short code
- Prot Resting 12h Ur-mRate
- Synonyms
- Prot Resting 12h Ur-mRate
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- 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
Why This Test Is Done
Your doctor may order this test if they suspect kidney disease, poor kidney function, or if you have conditions like diabetes or high blood pressure that can affect kidney health. It helps track how well your kidneys are working over time.
What to Expect Before the Test
You’ll collect all your urine for 24 hours, starting and ending at the same time each day. Drink plenty of fluids but avoid excessive salt or certain medications that could affect results. Bring a clean container and record all urine output.
What Happens During the Test
You’ll provide a blood sample (usually from a vein in your arm) to measure baseline creatinine levels. The urine sample is tested for creatinine concentration, and the rate is calculated based on urine volume and blood levels.
What the Results Mean
Results help determine if your kidneys are filtering waste efficiently. Abnormal rates may indicate kidney damage, fluid imbalance, or other health issues requiring further evaluation.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
This test is critical for diagnosing and monitoring chronic kidney disease, assessing hydration status, or evaluating the impact of medications on kidney function. It provides a comprehensive view of kidney performance over a full day, unlike single-point blood tests.
Short name
24h Urine Cr/Cr Rate
Frequently asked questions
How is this test different from a standard creatinine blood test?
What should I do if I miss collecting urine for part of the day?
Can I take my usual medications during the urine collection period?
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