A BUN, or blood urea nitrogen test, measures the amount of urea nitrogen in your blood. Urea nitrogen is a waste product created when your body breaks down protein. Your kidneys normally filter this waste product from your blood and remove it when you urinate.
A BUN level can be used to evaluate kidney function. High BUN levels may indicate that your kidneys are not working properly. However, other factors can also contribute to high BUN levels, such as dehydration, a high-protein diet, or certain medical conditions.
Normal BUN levels generally range from 6 to 24 mg/dL (2.1 to 8.5 mmol/L). The exact normal range may vary slightly depending on the laboratory and the individual's age and health.
A doctor may order a BUN test if you have symptoms of kidney problems, such as:
- Swelling in your legs or ankles
- Fatigue
- Loss of appetite
- Nausea
- Frequent urination
- Blood in your urine
A BUN test is a simple and painless blood test. Your doctor will order the test, and a healthcare professional will draw a small sample of your blood.
The BUN test results are often used in conjunction with other tests, such as a creatinine test, to provide a more complete picture of your kidney function.
