Definitions for "Blood Urea Nitrogen"
A product of metabolism that is excreted in the urine. It is measured in the blood as an indirect measure of how well the kidney is functioning. Increased BUN levels in the blood may indicate early kidney damage, meaning the kidneys aren't effectively excreting BUN.
A waste product in the blood that comes from the breakdown of food protein. The kidneys filter blood to remove urea. As kidney function decreases, the BUN level increases.
The term BUN refers to the substance urea, which is the major breakdown product of protein metabolism, and is ordinarily removed by the kidneys. During kidney failure, ure accumulates in proportion to the degree of kidney failure and to the amount of protein breakdown. The symptoms of uremia correspond roughly to the amount of urea in the blood stream.