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This BUN to urea converter changes blood urea nitrogen results into equivalent total urea values and performs the reverse urea to BUN conversion. BUN and urea describe related measurements, but they are not interchangeable labels for the same numerical result.
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重要な検査上の注意
What Is the Difference Between BUN and Urea?
Urea is a nitrogen-containing waste product formed mainly in the liver during protein metabolism. It circulates in the blood and is eliminated primarily through the kidneys.
BUN means blood urea nitrogen. A BUN result reports only the nitrogen contained within the urea molecule, while a urea result reports the mass or molar concentration of the complete urea molecule. This is why the numerical values are different even when they represent the same sample.
BUN to Urea Conversion
To convert BUN from mg/dL to urea in mmol/L, multiply the BUN result by 0.357. For example, 20 mg/dL BUN multiplied by 0.357 equals approximately 7.14 mmol/L urea.
To convert BUN from mg/dL to total urea in mg/dL, multiply by approximately 2.144. A BUN result of 20 mg/dL therefore corresponds to approximately 42.9 mg/dL of total urea.
- Urea mmol/L = BUN mg/dL × 0.357
- Urea mg/dL = BUN mg/dL × 2.144
- Urea mg/L = BUN mg/dL × 21.44
Urea to BUN Converter
The calculator also works in the reverse direction. To convert urea in mmol/L to BUN in mg/dL, multiply the urea value by 2.801.
If total urea is reported in mg/dL, multiply it by approximately 0.466 to obtain BUN in mg/dL.
- BUN mg/dL = Urea mmol/L × 2.801
- BUN mg/dL = Urea mg/dL × 0.466
- BUN mg/L = Urea mmol/L × 28.01
Common BUN and Urea Conversion Examples
The following examples illustrate commonly requested BUN to urea and urea to BUN conversions. Values are rounded for practical display.
- BUN 10 mg/dL = approximately 3.57 mmol/L urea
- BUN 20 mg/dL = approximately 7.14 mmol/L urea
- BUN 30 mg/dL = approximately 10.71 mmol/L urea
- Urea 5 mmol/L = approximately 14.01 mg/dL BUN
- Urea 10 mmol/L = approximately 28.01 mg/dL BUN
- Urea 15 mmol/L = approximately 42.02 mg/dL BUN
Why BUN and Urea Values Cannot Be Compared Directly
A laboratory report showing BUN in mg/dL cannot be compared numerically with a report showing urea in mmol/L or total urea in mg/dL. The analyte expression and the measurement unit must both be considered.
For example, a BUN value of 20 mg/dL and a urea value of 20 mg/dL do not represent the same concentration. Converting the result first prevents errors when comparing reports from laboratories that use different reporting conventions.
Clinical Context and Important Limitations
BUN and urea concentrations can be affected by kidney function, hydration, protein intake, gastrointestinal bleeding, catabolic states, liver function, pregnancy, medications, and other clinical factors.
A converted number remains the same laboratory result expressed in another format. Conversion does not change its clinical meaning and does not replace interpretation by a qualified healthcare professional.
- Use the analyte name and unit printed on the original laboratory report.
- Do not enter a total urea value as BUN or a BUN value as total urea.
- Use the reference interval supplied by the laboratory that performed the test.
- Do not use this converter alone to diagnose kidney disease or dehydration.
Frequently Asked Questions
How do I convert BUN to urea? Multiply BUN in mg/dL by 0.357 to obtain urea in mmol/L, or multiply it by approximately 2.144 to obtain total urea in mg/dL.
How do I convert urea to BUN? Multiply urea in mmol/L by 2.801 to obtain BUN in mg/dL. If urea is reported in mg/dL, multiply it by approximately 0.466.
Are BUN and urea the same test? They are related but reported differently. BUN represents the nitrogen portion of urea, whereas total urea represents the complete molecule.
Can this converter diagnose kidney disease? No. It only converts equivalent reporting formats and does not interpret the medical cause of an abnormal result.