BUN: Blood Urea Nitrogen
See if your kidneys are working normally.
See if your kidney disease is getting
• See if treatment of your kidney disease
treatment is working.
• Check for severe dehydration.
Dehydration generally causes BUN levels to
rise more than creatinine levels. This causes
a high BUN-to-creatinine ratio. Kidney
disease or blockage of the flow of urine
from your kidney causes both BUN and
creatinine levels to go up.
• Creatinine is a chemical waste product that's
produced by your muscle metabolism and to a
smaller extent by eating meat. Healthy kidneys
filter creatinine and other waste products from
your blood. The filtered waste products leave
your body in your urine.
• If your kidneys aren't functioning properly, an
increased level of creatinine may accumulate in
your blood. A serum creatinine test measures
the level of creatinine in your blood and gives
you an estimate of how well your kidneys filter
(glomerular filtration rate).
• Bilirubin is a yellowish pigment found in
bile, a fluid made by the liver.
• A small amount of older red blood cells are
replaced by new blood cells every day.
Bilirubin is left after these older blood cells
are removed. The liver helps break down
that it can be removed
from the body in
• Large amounts of bilirubin in the blood can
lead to jaundice. Jaundice is a yellow color
in the skin, mucus membranes, or eyes.
• Jaundice is the most common reason to check
• Most newborns have some jaundice. The doctor or
nurse will often check the newborn's bilirubin level.
• Jaundice can occur if:
• Too many red blood cells are dying or breaking
down and going to the liver
• The liver is overloaded or damaged
• The bilirubin from the liver is unable to move
into the digestive tract properly
• Jaundice is often a sign of a problem with the
liver, gallbladder, or pancreas.
• The total protein test measures the total amount
of two classes of proteins found in the fluid
portion of your blood: albumin and globulin.
• Proteins are important parts of all cells and
tissues. For example, albumin helps prevent
fluid from leaking out of blood vessels.
Globulins are an important part of your immune
• This test is often done to diagnose nutritional
problems, kidney disease or liver disease. If
total protein is abnormal, further tests must be
done to identify the specific problem.