Blood urea nitrogen test

Blood urea nitrogen (BUN) test is a medical test commonly used to gauge the amount of urea nitrogen present in a person's blood. It is a routine test that helps healthcare professionals assess the functionality of the kidneys and the liver, and to monitor the effectiveness of dialysis treatment in patients with chronic kidney disease.

Overview

Urea nitrogen is a waste product that is created in the liver when the body breaks down protein. It is then transported through the bloodstream to the kidneys, which filter it out of the blood and excrete it in the urine. The BUN test measures the amount of urea nitrogen in the blood, providing an indication of how well the kidneys and liver are functioning.

Procedure

The BUN test is a simple blood test. A healthcare professional will draw a small amount of blood from a vein, usually in the arm. The blood sample is then sent to a laboratory for analysis. The results are usually available within a few hours to a few days.

Interpretation of Results

The normal range for BUN levels can vary depending on the laboratory, but generally, a normal range is considered to be between 7 and 20 milligrams per deciliter (mg/dL). Higher than normal levels may indicate conditions such as kidney disease, liver disease, or congestive heart failure. Lower than normal levels may be seen in conditions such as liver failure, malnutrition, or overhydration.

Risks and Considerations

The BUN test is generally safe with minimal risks. Some people may experience minor bruising at the site where the blood was drawn. There is also a small risk of infection at the puncture site.

See Also

• Kidney function tests
• Liver function tests
• Urine tests