Creatinine Clearance (24-hour urine collection)
This test measures how well your kidneys filter waste products from your blood over a 24-hour period, using urine and blood samples.
["Assesses kidney function by evaluating how efficiently your kidneys remove waste."]
Key facts at a glance
- LOINC
- 19409-2
- Short code
- Cocaethylene CtO Ur Scn-mCnc
- Synonyms
- Cocaethylene CtO Ur Scn-mCnc
- Category
- chemistry
- Sample
- urine
- Container
- Sterile urine container
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- screen
- 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 Matters
Creatinine clearance helps doctors check how well your kidneys are working. It’s important because kidney function affects many other parts of your body, including your blood pressure, heart, and bones. If your kidneys aren’t filtering waste properly, it can lead to health problems over time.
How the Test Works
You’ll provide a 24-hour urine sample (collected in a special container) and a blood sample. The urine is tested for creatinine levels, while the blood is tested for creatinine and other factors like blood urea nitrogen (BUN). The test compares how much creatinine is in your urine versus your blood to calculate clearance.
Preparation for the Test
You’ll need to collect all urine for a full 24-hour period (from one full day to the next). Drink plenty of fluids but avoid special diets unless instructed by your doctor. Store the urine in a cool place and bring the container and all samples to your lab visit.
What to Expect During the Test
The urine collection is straightforward—just empty your bladder into the container every time you urinate, including first thing in the morning. The blood draw is quick and done in a clinic or lab. You may feel slight discomfort, but it’s usually over quickly.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
None
Frequently asked questions
A creatinine clearance test is critical for diagnosing and monitoring kidney disease. Low clearance may indicate impaired kidney function, while high clearance could suggest overhydration or other conditions. It’s often used alongside other tests to assess kidney health, especially in people with symptoms like fatigue, swelling, or frequent urination.
How often should I get this test?
What happens if my results are abnormal?
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