What is a Blood Urea Nitrogen (BUN)?
Urea is a nitrogenous waste product produced as a result of protein metabolism in the liver, the urea then travels to the kidney for excretion through the bloodstream. Blood urea nitrogen (BUN) is an essential biomarker for the assessment of kidney health, liver dysfunction, and the hydration status of the body.
BUN test is usually suggested along with other diagnostic tests to get a complete picture of the body’s overall health, particularly kidney and liver function. Abnormal levels of BUN indicate that the person is affected by an underlying condition such as kidney disorders, liver diseases, dehydration, and heart failure.
How is the Test Performed?
The Blood Urea Nitrogen (BUN)Test is a part of the basic metabolic panel (BMP) or comprehensive metabolic panel (CMP) and involves a simple blood draw;
Preparation
- If BUN is part of the CMP then fasting of 6 to 8 hours is generally required.
- Avoid overconsumption of protein before the test.
- Keep yourself hydrated and take a normal diet.
- Inform your doctor about the medications you are taking as certain medicines might interfere with the test result and needs to be avoided.
Blood Draw
- A trained phlebotomist draws blood from the vein and the sample is sent to the laboratory for further analysis.
Laboratory Analysis
- Automated analyzers measure the BUN levels present in the blood sample.
What are the symptoms that prompt this test?
The blood urea nitrogen test is suggested to the individuals at risk of kidney or liver disorders and are exhibiting symptoms associated with this condition.
General symptoms
- Dry mouth
- Increased thirst
- Abnormal weight loss
- Dark urine or pale stool
- Edema
- Jaundice
- Nausea or vomiting
What are Normal Ranges for This Test?
The levels of Blood Urea Nitrogen (BUN) vary with age, gender, hydration status, and kidney function. The generally accepted reference range for BUN is given below;
Adults – 6 to 24 mg/dL
Children – 5 to 18 mg/dL
**The reference values given above are for general guidelines only and may vary between laboratories due to the assay of the test. **
What Happens if Test Results Show Abnormal Levels?
Elevated or lowered level of BUN indicates that the kidneys are not functioning properly and the liver and hydration status is also affected;
Increased Blood Urea Nitrogen (BUN)
- Gastrointestinal bleeding
- Kidney dysfunction- acute or chronic kidney disease
- Heart failure
- Dehydration
- High intake of dietary protein
- Might be due to the use of certain medications
Decreased Blood Urea Nitrogen (BUN)
- Liver damage
- Low intake of protein in the diet
- Pregnancy
- Overhydration
Managing the abnormal levels of BUN is crucial for the normal functioning of the body, the underlying conditions are usually managed by dietary adjustment, medications, and regular monitoring of the disease.
