Urine Free Creatinine-to-Creatinine Clearance Ratio
This test measures how well your kidneys filter waste products by comparing urine and blood levels of creatinine, a waste product from muscle metabolism, without relying on a timed urine collection.
["Assesses kidney function and filtration efficiency using a simple urine sample."]
Key facts at a glance
- LOINC
- 12777-9
- Short code
- Kappa LC Free Ur-aCnc
- Synonyms
- Kappa LC Free Ur-aCnc
- 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
How the Test Works
Your urine sample is analyzed to determine the concentration of creatinine. Blood is also drawn to measure baseline creatinine levels. The test calculates clearance by comparing these values, providing an estimate of kidney function without needing a 24-hour urine collection.
Why It’s Done
Doctors may order this test to evaluate kidney health, especially if you have symptoms like fatigue, swelling, or changes in urine output, or if you have conditions like diabetes or high blood pressure that can affect kidney function.
Sample Collection
A simple urine sample is collected (often a random sample) and sent to the lab. Blood may also be drawn for baseline creatinine measurement. No special preparation is needed, but drinking extra water beforehand can help ensure accurate results.
What to Expect
The urine test is quick and painless. Blood drawing may cause slight discomfort but is typically over quickly. Results are usually ready within a few days.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Urine Free Cr Clearance
Frequently asked questions
This test helps identify kidney dysfunction by measuring how efficiently your kidneys remove waste products. Low clearance may indicate impaired kidney function, while high values could suggest overhydration or other conditions. It’s particularly useful for monitoring chronic kidney disease or assessing kidney response to treatment.
Results are usually available within 1–3 business days, depending on your lab’s processing time. Your healthcare provider will discuss them with you during your follow-up visit.
A lower-than-expected clearance may signal reduced kidney function, which could be due to chronic kidney disease, dehydration, or other health conditions. Your doctor will interpret results in the context of your medical history and symptoms.
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