Mediki
Urea (BUN) blood test: what your result means
Urea (BUN) measures a protein metabolism waste product removed by the kidneys. It helps assess hydration and kidney handling.
- Category
- Kidney function
- Standard unit
- mmol/L
- Also called
- BUN
- Reported in
- mmol/L, µmol/L, mg/dL, mg/100mL, mg%, mg/L and more
What does high urea (BUN) mean?
Higher values may suggest dehydration, increased protein breakdown, or reduced kidney clearance. What counts as high depends on the reference range printed on your lab report, because ranges differ between laboratories.
What does low urea (BUN) mean?
Lower values may suggest low protein production/intake or dilution. What counts as low depends on the reference range printed on your lab report, because ranges differ between laboratories.
Urea (BUN) units and conversion
Mediki shows urea (BUN) in mmol/L. Labs may report it in other units; Mediki converts them automatically so results from different labs line up on one chart.
| Unit on your report | Convert to mmol/L | Convert back |
|---|---|---|
| µmol/L | 1 µmol/L = 0.001 mmol/L | 1 mmol/L = 1,000 µmol/L |
| mg/dL, mg/100mL, mg% | 1 mg/dL = 0.3571 mmol/L | 1 mmol/L = 2.8 mg/dL |
| mg/L, µg/mL | 1 mg/L = 0.03571 mmol/L | 1 mmol/L = 28 mg/L |
Convert a value from your report with the blood test unit converter.
Why track urea (BUN) over time?
A single urea (BUN) result is a snapshot. Comparing it with your earlier tests shows whether a value is stable, slowly drifting, or responding to a change in treatment or lifestyle, which is often more useful than one number on its own.
Read our guide on how to read blood test results to understand reference ranges, flags and units.
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Medical disclaimer: This page is general information, not medical advice. Reference ranges differ between laboratories, and only a doctor can interpret your results in the context of your health.