Blood urea nitrogen

Blood urea nitrogen (English blood urea nitrogen ), usually with BUN abbreviated, is a measure of the nitrogen content of the metabolic end product of urea in the blood . It is given in mmol / l ( SI unit ) or in mg / dl (outdated). Since every urea molecule ( molar mass60.06 g) contains two nitrogen atoms (molar mass 28.01 g), the concentration of the nitrogen content ('BUN') in mg / dl can easily be calculated from the urea concentration in mg / dl by multiplying the urea concentration by 0.467 becomes. Since two nitrogen atoms make up one nitrogen molecule, i.e. one mole of urea contains practically one mole of nitrogen (considered as N2), the urea concentration given in mmol / l is identical to the urea nitrogen concentration given in mmol / l (conversion factor 1.0).

The liver produces urea in the urea cycle as a waste product from protein digestion . Normal human blood serum should contain between 7 and 25 mg of urea nitrogen per 100 ml. However, individual laboratories may specify different limit values ​​due to different test procedures.

The BUN is one of the kidney retention parameters and is mainly used as a medical indicator in nephrology . The determination of the BUN is often carried out in the Anglo-American language area, while z. B. in Germany the urea concentration is determined instead.

unit

The conversion from mg / dL to mmol / L is done by multiplying by 0.357.

References and comments

1. ↑ Fluitest UREA
2. ↑ Laborlexikon.de
3. ↑ A urea molecule contains two nitrogen atoms, one mole of urea therefore contains 28 g of nitrogen, so that one milligram is 0.0357 millimole.

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