Blood Urea Nitrogen (BUN) Serum Older adult (> 60 years): 8-21 mg/dl Child to adult (1-40 years): 5-20 mg/dl Infant (birth-1 years): 4-16 mg/dl To evaluate renal function To monitor patients in renal failure or those receiving dialysis therapy Acute or chronic renal failure Shock Renal artery stenosis Hemorrhage Postrenal obstruction Stress Congestive Heart Failure Burns Increased protein intake Dehydration Hyperalimentation Ketoacidosis Diabetes mellitus Long-term steroid therapy Overhydration Starvation Intravenous therapy Low-protein diet Acromegaly Severe liver damage