Urinary Creatinine-to-Creatinine Clearance Ratio (24-hour urine collection)
This test measures how well your kidneys filter waste products from your blood by analyzing urine collected over 24 hours.
["Assesses kidney function by evaluating urine flow and waste removal efficiency over a full day."]
Key facts at a glance
- LOINC
- 30877-5
- Short code
- NM Kidney+ves Views W RNC IV
- Synonyms
- NM Kidney+ves Views W 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
What This Test Measures
The test evaluates two key aspects: the amount of creatinine in your urine and how much creatinine your body produces. Creatinine is a waste product from muscle metabolism that kidneys normally filter out. By comparing urine creatinine levels to blood creatinine levels (not directly measured here), doctors estimate how effectively your kidneys are working to clear waste.
Why It’s Done
A 24-hour urine creatinine-to-creatinine clearance ratio may be ordered to diagnose or monitor kidney disease, evaluate chronic kidney conditions, or assess how well medications are being cleared by the kidneys. It can also help identify issues like kidney stones, urinary tract obstructions, or improper hydration.
Sample Collection Process
You’ll collect all urine for a full 24-hour period, typically starting after midnight and ending the next midnight. A healthcare provider will give you a clean container to store the urine. Empty your bladder at the start and end of the collection period, then discard those samples. Store the urine in a cool place and return it to the lab on ice or refrigerated.
Preparation and Timing
No special diet or restrictions are needed, but avoid taking certain medications that could affect urine composition. Follow your doctor’s instructions precisely for timing and collection. If you forget to collect urine, ask your lab about alternative methods (e.g., timed samples).
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
None
Frequently asked questions
This test helps determine if your kidneys are functioning normally by measuring how efficiently they filter waste. Low clearance may indicate kidney damage, poor blood flow, or urinary tract blockages, while high clearance could suggest dehydration or overactive urine production. It’s particularly useful for chronic kidney disease monitoring where blood tests alone may not provide enough detail.
A low clearance result suggests your kidneys are not filtering waste as well as they should, which could indicate chronic kidney disease, reduced blood flow to the kidneys, or other underlying conditions like diabetes or hypertension.
Results typically take 1–3 business days after the lab processes your 24-hour urine sample. Your doctor will discuss the findings with you during your follow-up appointment.
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