Serum or plasma mass concentration of portal vein blood urea nitrogen (BUN)
This test measures the amount of urea nitrogen in blood taken from the portal vein, which carries blood from the digestive system to the liver. It helps assess liver function and blood flow in the portal circulation.
["This test helps doctors evaluate liver health and blood flow to the liver."]
Key facts at a glance
- LOINC
- 36077-6
- Short code
- MRA Portal v
- Synonyms
- MRA Portal v
- 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-angio
- 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 the Purpose of This Test?
Doctors may order a portal vein BUN test to check for conditions affecting the liver’s ability to process blood, such as cirrhosis, portal hypertension, or blockages in the portal vein. It can also help diagnose or monitor liver diseases or conditions like portal vein thrombosis.
How Is the Sample Collected?
A blood sample is drawn from a vein, usually in your arm, and sent to a lab. The blood is taken directly from the portal vein, often during a procedure like a liver biopsy or endoscopic retrograde cholangiopancreatography (ERCP).
What Does a Result Mean?
Higher than expected levels may suggest poor liver function, reduced blood flow to the liver, or blockages in the portal vein. Lower levels might indicate conditions where blood bypasses the liver (such as shunts) or liver disease progression. Results are interpreted by your healthcare provider in the context of your overall health.
Common Conditions Monitored
This test is often used alongside other liver function tests to diagnose or monitor conditions like cirrhosis, portal hypertension, liver tumors, or vascular diseases affecting the liver’s blood supply.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Clinical Significance: Portal vein BUN is less commonly used than standard BUN tests but can provide critical insights in specialized cases, such as evaluating portal hypertension or assessing liver perfusion in advanced liver disease. It complements other tests like liver enzymes or imaging studies for a full assessment.
Short name
Portal vein BUN
Frequently asked questions
Why might my doctor request this test?
What preparation is needed before the test?
Are there any risks or side effects?
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