Understanding This Medical Test and Your Results
This test measures the amount of urea nitrogen in your urine, helping evaluate kidney function and protein metabolism in your body.
{"Measures urea nitrogen levels in urine to assess kidney function","Helps monitor protein metabolism and dietary protein intake","A 24-hour urine collection is typically required","Results can be affected by diet, kidney function, and certain medications","Abnormal results may indicate kidney disease or metabolic disorders"}
Key facts at a glance
- LOINC
- 35235-1
- Short code
- UUN
- Synonyms
- UUN Ur-msCnc
- Category
- chemistry
- Sample
- urine
- Container
- Clean, sterile plastic urine container with preservative (typically hydrochloric acid or thymol) for 24-hour collection
- Units
- not specified
- Ref low
- 12
- Ref high
- 20
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- ≥ 0 years
- Method
- Enzymatic spectrophotometric method (urease-mediated reaction) or colorimetric method
- CPT
- 84540
- SNOMED
- 271656006
- Specimen volume
- Minimum 10 mL, preferred 50-100 mL for complete 24-hour collection
- 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
- 4–24 hours
- Order
- routine
What is this test? This medical test evaluates a specific aspect of your health, such as how an organ functions, whether an infection is present, or whether certain conditions may need further evaluation.
The urine urea nitrogen test measures the concentration of urea nitrogen in your urine. Urea is a waste product formed when your body breaks down protein. Healthy kidneys filter urea from the blood and excrete it in urine. This test helps doctors understand how well your kidneys are working and how your body is processing protein.
How is the test performed? Depending on the type of test, a healthcare professional may collect a blood, urine, saliva, or tissue sample, or use imaging or monitoring equipment. You will receive instructions about preparation and what to expect.
You will typically need to collect all urine produced over a 24-hour period. This is called a 24-hour urine collection. You will be given a special container to collect your urine. During the collection period, keep the container refrigerated or in a cool place. Make sure to label the container with your name, date, and time of collection.
What do the results mean? Results are interpreted using reference ranges, your symptoms, medical history, and other findings. An abnormal result does not always indicate disease, so discuss the meaning and any recommended follow-up with your healthcare professional.
Normal urine urea nitrogen levels vary depending on your diet and kidney function. Higher than normal levels may indicate high protein intake, kidney problems, or certain medical conditions. Lower than normal levels may suggest kidney disease, liver disease, or malnutrition. Your doctor will interpret your results based on your overall health and other test results.
Reference range
12-20 g/24 hnot specified
24-hour urine collection recommended; no fasting or special diet required
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
The urine urea nitrogen test is primarily used to evaluate kidney function and assess protein metabolism. It helps doctors diagnose and monitor kidney diseases, track the progression of kidney dysfunction, and evaluate the effectiveness of treatment. The test can also help distinguish between different types of kidney problems and assess dietary protein intake.
Frequently asked questions
Do I need to fast before the test?
Will my diet affect the results?
Can medications affect the test results?
Is the 24-hour urine collection necessary?
What happens if my results are abnormal?
Sources
- 1
- 2
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