What it means
Both 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 and creatininekree-AT-uh-neenA waste product of muscle that the kidneys remove from the blood; its blood level is used to measure how well the kidneys work.Full entry rise when the kidneys filter poorly. Comparing them helps tell why. When the kidneys themselves are damaged, both rise together and the ratio stays near normal. When too little blood reaches the kidneys, as with dehydration or heart failure, BUN rises more than creatinine and the ratio climbs above 20:1; bleeding in the upper gut and a high-protein intake can raise it too.
At a glance
| Normal range | About 10:1 to 20:1 |
|---|---|
| Also written | BUN to creatinine ratio, BUN/creatinine ratio, BUN:creatinine ratio |
Related terms
dehydration
A state in which the body has lost more water than it has taken in.
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.