What is the normal value for blood urea nitrogen (BUN)?
Disease description:
During my physical examination, I found that my blood urea nitrogen (BUN) level was elevated. What is the normal reference range for BUN?
Doctor's answer (1)
Dr. Tan Bo
The normal reference range for blood urea nitrogen (BUN) also varies with age: in newborns, it is typically 1.4–4.3 mmol/L; in children, 1.8–6.4 mmol/L; in adults, 2.5–6.4 mmol/L; and in the elderly, 2.9–7.5 mmol/L.
Urea nitrogen is a metabolic byproduct of protein breakdown in the human body and is primarily excreted by the kidneys; approximately 10% is eliminated via the gastrointestinal tract and skin. When renal function is impaired, these metabolic waste products cannot be adequately excreted, leading to elevated BUN levels.
