BUN levels: what's normal, high and low
Nitrogen waste from protein metabolism that your kidneys clear. A general kidney-function indicator.
Medically reviewed by Youmna DiStefano, MD · Last reviewed September 2026
The short answer
BUN is measured with a standard blood draw after an 8–12 hour fast. A typical reference range is 7.00 – 20.0 mg/dL. At TestWell it's $20.99 all-in as Basic Metabolic Panel, results in 1–3 business days, drawn at Quest or Labcorp. An out-of-range result is a prompt to look closer, not a diagnosis.
- Units
- mg/dL
- Sample
- Blood draw
- Fasting
- 8–12 hours
- Results
- 1–3 business days
- Price
- $20.99
- Labs
- Quest or Labcorp · BioReference in NY/NJ
BUN Reference Range
These are the typical adult reference ranges used by major US labs. Your report will include the specific range used by the lab that processed your sample.
| Population | Range |
|---|---|
| age 18+ | 7.00 – 20.0 mg/dL |
Reference ranges are educational. Always interpret your result with the specific range printed on your lab report and discuss anything outside the range with a clinician.
What your BUN result may mean
Often reflects dehydration, high-protein diets, or reduced kidney function.
What a high BUN means: causes, symptoms, next steps →Can reflect low-protein intake, liver disease, or overhydration.
What a low BUN means: causes, symptoms, next steps →Educational only — not a diagnosis. Many factors can influence a single result. Discuss anything that concerns you with a healthcare provider.
How do you get a BUN test?
Order online, a licensed physician reviews the requisition, and you walk into a nearby lab for the draw. BUN is available on its own or inside these panels — panels cost less per marker when you want the fuller picture.
| Option | Includes | Price |
|---|---|---|
| Basic Metabolic Panel | This marker only | $20.99 |
Quest vs. Labcorp for BUN: which lab should you pick?
Both are CLIA-certified national labs and the result is clinically equivalent, so pick whichever location is closer. Your report will print that lab's own reference range, which can differ slightly from the table above.
| Lab | Available | Price |
|---|---|---|
| Quest Diagnostics | Yes | $20.99 |
| Labcorp | Yes | $21.99 |
| BioReference (NY & NJ) | Yes | $22.99 |
Need help choosing a location? Use the lab finder to see draw sites near your ZIP.
Related Metabolic Health biomarkers
Markers commonly tested alongside BUN.
Frequently asked
Often reflects dehydration, high-protein diets, or reduced kidney function. A single result above the reference range is a prompt to look closer with a clinician — often a repeat test and related markers — not a diagnosis on its own.
Ready to test your bun?
Order in two minutes, get physician-approved, and visit a lab the same day. Starts at $20.99.