Urine Creatinine Excretion Rate
This test measures the amount of creatinine your kidneys remove from your blood and pass into your urine over a set period, helping your doctor evaluate how well your kidneys are working.
{"Measures creatinine excretion rate from a urine sample","Helps evaluate how well your kidneys are working","Used to verify proper urine collection and calculate other test results","Abnormal results may indicate kidney problems","Often part of kidney function assessment panels"}
Key facts at a glance
- LOINC
- 72821-2
- Short code
- U_CREAT_CALC
- Synonyms
- Creat ?Tm Ur Calc-mRate
- Category
- kidney
- Sample
- urine
- Container
- Sterile urine collection container (clean-catch or catheterized)
- Units
- not specified
- Ref low
- 0.5
- Ref high
- 2
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- calculated
- CPT
- 82570
- SNOMED
- 271254004
- Specimen volume
- Minimum 10 mL; optimal 50-100 mL for timed collections
- Stability
- Room temperature: 24-48 hours; Refrigerated (2-8°C): 5-7 days; Frozen (-20°C): several weeks
- Hemolysis max
- 0
- Lipemia max
- 0
- Icterus max
- 0
- TAT
- 2–24 hours
- Order
- routine
What is this test?
The urine creatinine excretion rate test measures the amount of creatinine your body produces and excretes through your urine over a specific period. Creatinine is a waste product created when muscles break down creatine, a substance used for energy. Normally, your kidneys filter creatinine from your blood and eliminate it in urine. This test calculates how much creatinine passes through your kidneys in a given time frame, usually expressed as milligrams per day (mg/24h) or millimoles per day (mmol/24h).
Why do I need this test?
Your doctor may order this test to: assess how well your kidneys are filtering waste products; verify that you collected your urine sample correctly (especially for 24-hour urine collections); calculate the excretion rates of other substances like protein or albumin in your urine; monitor kidney function if you have conditions like diabetes, high blood pressure, or kidney disease; and check for abnormalities in kidney function before starting certain medications.
How is the test performed?
For this test, you will typically collect all urine produced over a 24-hour period in a special container provided by your laboratory. It's important to: collect your first morning urine and flush it down the toilet, then start timing; collect all subsequent urine including the first morning sample of the next day; keep the container refrigerated or in a cool place; and return the complete collection to the lab as instructed. Some tests may use a single urine sample rather than a 24-hour collection.
What do the results mean?
Normal creatinine excretion rates vary based on age, gender, muscle mass, and body size. Generally, normal ranges are approximately: 15-25 mg/kg/day for adult females and 20-30 mg/kg/day for adult males. Higher than expected creatinine excretion typically indicates a complete and accurate urine collection. Lower than expected results may suggest: incomplete urine collection; reduced muscle mass; kidney disease affecting filtration; or conditions that impair kidney function.
Reference range
0.5-2.0 g/day (varies by sex, age, muscle mass; often 1.0-2.0 g/day males, 0.8-1.8 g/day females for 24h)not specified
Complete timed urine collection over specified duration required; no fasting needed
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The urine creatinine excretion rate is primarily used as a quality check for 24-hour urine collections. If your creatinine excretion is lower than expected for your body size, it suggests the urine collection may be incomplete, which could affect other test results from the same sample. This test is also valuable for monitoring patients with chronic kidney disease (CKD), diabetes-related kidney damage, or those taking medications that may affect kidney function. Additionally, creatinine excretion rate helps calculate the urine protein-to-creatinine ratio, which is used to diagnose and monitor proteinuria (excess protein in urine), an important indicator of kidney damage.
Frequently asked questions
Do I need to fast before this test?
Can medications affect my results?
What happens if my results are abnormal?
How do I ensure an accurate 24-hour urine collection?
Is this test safe?
Sources
- 1
- 2
- 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