kidney · BUN
Blood Urea Nitrogen
A waste product from protein breakdown that the kidneys clear. It rises with reduced kidney function but is also strongly affected by hydration, protein intake, and other factors, so it's read alongside creatinine and eGFR.
This page is general wellness education, not medical advice. Your own lab’s reference range and your clinician’s interpretation always take precedence.
Typical reference range
| Group | General range |
|---|---|
| Adults | 6 – 20 mg/dL |
Units: mg/dL. Ranges vary by lab and assay — read yours against the range printed on your own report.
What high Blood Urea Nitrogen can mean
- Dehydration
- Reduced kidney function
- High protein intake
- GI bleeding
- Some medications
What low Blood Urea Nitrogen can mean
- Low protein intake
- Liver disease
- Overhydration
- Pregnancy