- : Blood urea nitrogen. A measure primarily of the urea level in blood. Urea is cleared by the kidney and diseases which compromises the function of the kidney will frequently lead to increased blood levels. The blood BUN level can also rise in patients who are dehydrated.
* * ** * *blood urea nitrogen
* * *BUN .bē-.yü-'en n the concentration of nitrogen in the form of urea in the blood
* * *blood urea nitrogen; see urea nitrogen, under urea.
Medical dictionary. 2011.