Urine Creatinine-to-Creatinine Clearance Ratio (24-hour collection)
This test measures how well your kidneys filter waste products by comparing creatinine levels in your urine and blood over a 24-hour period.
["Assesses kidney function by evaluating how efficiently waste is removed from your blood."]
Key facts at a glance
- LOINC
- 9942-4
- Short code
- Q wave dur L-III
- Synonyms
- Q wave dur L-III
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- ekg
- 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 Matters
Kidneys play a vital role in filtering waste and excess substances from your blood. This test helps doctors check if your kidneys are working properly by tracking how well they clear creatinine, a waste product from muscle metabolism.
How It’s Done
You’ll collect all your urine over 24 hours in a special container. Blood is drawn once to measure your baseline creatinine level. The test compares these two measurements to estimate kidney function.
What to Expect Before the Test
No special preparation is needed, but drink plenty of water to ensure your urine is clear. Avoid certain medications that may affect kidney function, and inform your doctor about any allergies or health conditions.
Possible Results and Interpretation
Results are used to calculate your creatinine clearance rate. Lower than expected values may indicate kidney problems, while higher values could suggest dehydration or other conditions. Your doctor will interpret results in relation to your overall health.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Urine Creatinine Clearance
Frequently asked questions
This test is crucial for diagnosing and monitoring kidney disease, including chronic kidney disease (CKD), kidney stones, or other conditions affecting kidney function. It helps track how well treatment is working over time.
A low creatinine clearance may signal that your kidneys are not filtering waste efficiently, which could be due to kidney damage, disease, or other health issues. Your doctor will discuss this with you during your follow-up.
Yes, high-protein foods or muscle mass can temporarily raise creatinine levels. Avoid extreme diet changes before testing, and follow your doctor’s advice for optimal results.
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