What is the normal BUN range?

What is the normal BUN range?

• A. 7–20 mg/dL
• B. 10–30 mg/dL
• C. 5–15 mg/dL
• D. 15–40 mg/dL

Answer: (A)

BUN reflects how well the kidneys are clearing nitrogen waste from protein metabolism. The normal range is about 7–20 mg/dL, which indicates the kidneys are filtering urea effectively. Values higher than this can point to reduced kidney function or factors that raise urea production or reabsorption, such as dehydration, high protein intake, or certain medications. Values lower than this can occur with liver disease, malnutrition, or overhydration, where urea production or concentration is reduced. In practice, clinicians also look at the BUN-to-creatinine ratio to help distinguish whether a high BUN is due to pre-renal factors (like dehydration) or intrinsic kidney problems.

BUN reflects how well the kidneys are clearing nitrogen waste from protein metabolism. The normal range is about 7–20 mg/dL, which indicates the kidneys are filtering urea effectively. Values higher than this can point to reduced kidney function or factors that raise urea production or reabsorption, such as dehydration, high protein intake, or certain medications. Values lower than this can occur with liver disease, malnutrition, or overhydration, where urea production or concentration is reduced. In practice, clinicians also look at the BUN-to-creatinine ratio to help distinguish whether a high BUN is due to pre-renal factors (like dehydration) or intrinsic kidney problems.