Test Overview
A blood urea nitrogen (BUN) test measures
the amount of nitrogen in your blood that comes from the waste product
. Urea is made when protein is broken down in your
body. Urea is made in the
and passed out of your body in the urine.
A BUN test is done to see how well your
are working. If your kidneys are not able to
remove urea from the blood normally, your BUN level rises.
,
, or a diet high in protein can also make
your BUN level higher. Liver disease or damage can lower your BUN level. A low
BUN level can occur normally in the second or third
of pregnancy.
Blood urea nitrogen to creatinine ratio (BUN:creatinine)
A BUN test may be done with a blood
test. The level of creatinine in your blood
also tells how well your kidneys are working—a high creatinine level may mean
your kidneys are not working properly. Blood urea nitrogen (BUN) and creatinine
tests can be used together to find the BUN-to-creatinine ratio
(BUN:creatinine). A BUN-to-creatinine ratio can help your doctor check for
problems, such as dehydration, that may cause abnormal BUN and creatinine
levels.