Serum or plasma mass concentration of urea nitrogen (Urea Nitrogen, Urea Content)
This test measures the amount of nitrogen found in your blood that comes from urea, a waste product produced when your body breaks down proteins.
["Helps assess kidney function and fluid balance by tracking urea levels in your blood."]
Key facts at a glance
- LOINC
- 26232-9
- Short code
- MR UE-Bl
- Synonyms
- MR UE-Bl
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (SST)
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- mr
- 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
What Is Urea Nitrogen Used For?
Urea nitrogen is primarily used to evaluate kidney function. High levels may indicate impaired kidney filtering, while low levels could suggest dehydration or other conditions affecting fluid balance.
How Is the Test Performed?
A blood sample is drawn from a vein, usually in your arm. The sample is sent to a lab where it is analyzed to measure the amount of urea nitrogen present.
What Does a High or Low Level Mean?
Elevated urea nitrogen levels often signal kidney problems, such as reduced blood flow or damage to kidney tissue. Very low levels might suggest dehydration, excessive fluid loss, or certain medical conditions.
Common Causes of Abnormal Results
Kidney disease or dysfunction is the most common cause of elevated urea nitrogen. Other factors include dehydration, heart failure, severe infections, or certain medications.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Urea Nitrogen (Urea Content)
Frequently asked questions
Why might my doctor order this test?
How long does it take to get results?
Can I eat or drink before this test?
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