Word parts
What it means
When the body uses protein, ammonia is left over. The liver turns this ammonia into urea, which is less harmful, and the kidneys filter it out. The amount of urea nitrogen in the blood is measured as blood urea nitrogenblud yoo-REE-uh NY-truh-jenA blood test that measures urea nitrogen, a waste product made when the body breaks down protein.Full entry (BUN), one of the main tests of kidney function. Urea is also used in some skin creams to soften dry skin.
For the nurse
A rising BUN can come from poor kidney function, dehydration, bleeding in the gut or a high-protein diet, so read it together with creatinine and the client's fluid status.
At a glance
| Spanish | urea |
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Related terms
renal
Relating to the kidneys.
creatinine
A waste product of muscle that the kidneys remove from the blood; its blood level is used to measure how well the kidneys work.
blood urea nitrogen
A blood test that measures urea nitrogen, a waste product made when the body breaks down protein.
kidney
One of two bean-shaped organs in the back of the belly that filter the blood and make urine.