Creatinine Clearance (24-hour urine collection)
This test measures how well your kidneys filter waste products from your blood over a full day. It helps assess kidney function and blood flow to the kidneys.
["A 24-hour urine test checks kidney health by tracking how efficiently your body removes creatinine."]
Key facts at a glance
- LOINC
- 7706-5
- Short code
- Johnson grass smut IgG Qn
- Synonyms
- Johnson grass smut IgG Qn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- CPT
- 82784
- 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 a 24-hour creatinine clearance test if they suspect kidney problems, such as chronic kidney disease, kidney stones, or improper kidney function. It’s also used to monitor kidney function in people with diabetes, high blood pressure, or other conditions that can affect the kidneys.
How the Test Works
You’ll collect all your urine for a full 24-hour period, typically starting and ending at the same time each day. The urine is then sent to a lab for analysis. Creatinine is a waste product from muscle metabolism that the kidneys filter out of the blood. Clearance measures how well your kidneys remove this waste.
Sample Collection Process
You’ll receive clear containers to store your urine in a timed manner. Empty your bladder at the start time (e.g., 8:00 AM), then collect every drop of urine for the next 24 hours. Discard the first morning urine if you missed the start time. Seal the containers and return them to your doctor’s office or lab on time.
What to Expect After the Test
After collection, the lab will analyze your urine sample to determine creatinine levels and calculate clearance. Results are compared to your body size and overall health to assess kidney function. Results may take several days to return.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Low creatinine clearance (below expected levels) may indicate kidney damage, poor blood flow to the kidneys, or other health issues. High clearance could suggest overhydration or errors in collection. This test is critical for diagnosing and managing kidney-related conditions, guiding treatment plans, and preventing complications like kidney failure.
Short name
24-Hour Creatinine Clearance
Frequently asked questions
How long does it take to get my results?
Can I eat or drink normally before this test?
What if I miss the start or end time for 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