How reports print it
BUNАзот мочевиныBlood urea nitrogenUrea nitrogenМочевина в сывороткеКарбамидМочевина в крови
What it shows
The end product of protein breakdown, cleared by the kidneys.
Units and conversion
Base unit: mmol/L.
- 1 mg/dL = 0.1665 mmol/L · 1 mmol/L = 6.006 mg/dL
- 1 mg/dL (urea nitrogen, BUN) = 0.357 mmol/L · 1 mmol/L = 2.801 mg/dL (urea nitrogen, BUN)
Typical ranges
Your laboratory’s range comes first — it is printed on the report next to the result. Below is one laboratory’s adult range with its method: a reference, not a rule.
| Who | Range, mmol/L |
|---|---|
| Adults, 18–19 years | 2.9–7.5 |
| Men, 20–50 years | 3.2–7.3 |
| Women, 20–50 years | 2.6–6.7 |
| Men, 51 years and older | 3–9.2 |
| Women, 51 years and older | 3.5–7.2 |
Range source: Лаборатория Хеликс — Мочевина в сыворотке
Good to know
US reports give blood urea nitrogen (BUN), not urea: urea in mmol/L = BUN in mg/dL × 0.357.
Why it can be higher
Common reasons discussed with a doctor. This is not a diagnosis.
- A high-protein diet
- Dehydration
- Some medicines, such as glucocorticoids
- Reduced kidney function
- Bleeding in the stomach or intestine
Why it can be lower
- A low-protein diet
- Pregnancy
- Liver conditions
- Excess fluid
What to ask a doctor
- How does urea fit with creatinine?
- Does my diet affect it?
Whom to see
A GP or internist.