Lupus Site - a guide for lupus patients and their families

This test determines the level of urea nitrogen in the blood. Urea nitrogen is produced when proteins are metabolized or broken down. Elevated levels of blood urea nitrogen (BUN) can be a sign of kidney disease, liver disease or dehydration.

This test is normally done to evaluate kidney function and aid in diagnosing kidney disease. It may also be performed to assess for dehydration.

Normal values for BUN are 7 to 20 milligrams per deciliter (mg/dl) of blood.

Levels lower than normal may indicate:

• liver failure

• a diet too low in protein

• malnutrition

• overhydration, or too much fluid in the body

Levels higher than normal may indicate:

• congestive heart failure, or heart disease

• starvation

• eating too much protein

• gastrointestinal bleeding

• burns

• dehydration, or not having enough fluids in the body

• myocardial infarction, or heart attack

• kidney disease

• kidney failure

• shock

• obstruction of the urinary tract