$Unique_ID{BRK01903}
$Pretitle{}
$Title{What is the "BUN"?}
$Subject{BUN blood kidney kidneys urea nitrogen checkup checkups examine
examination examinations creatinine uric acid renal artery urine chemical
chemicals test tests tested testing urea-nitrogen}
$Volume{}
$Log{
Anatomy of the Kidney*0004801.scf
Cross Section of a Kidney*0004901.scf
Formation of Urine*0015901.scf
Kidney Nephrons*0004902.scf}

Copyright (c) 1993  Tribune Media Services, Inc.


What is the "BUN"?


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QUESTION:  Every year my brother has to take a physical for the company he
works for.  In the report from the hospital it showed his "BUN" from the blood
test was 25, and higher than normal.  I know it has something to do with his
kidneys, and that kidney problems put our father on a machine for the last
year of his life.  Can you give us more information?

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ANSWER:  Your past experiences with your father have left you with an
understandable anxiety and concern for your brother, but the information
contained in your letter is not as frightening as you now believe.  To start
with, a finding of 25 for the BUN (blood urea nitrogen) is at the upper end of
the normal range.  Most of the blood tests taken during annual checkups are
"screening" examinations, and any abnormal result should be followed up by
another, perhaps more specific analysis.
     One of the major functions of the kidney is to rid the body of waste
products.  These substances include urea, creatinine and uric acid.  When the
blood enters the kidney by way of the renal artery, these substances are
filtered out of the blood, and are transferred into the urine.  When the urine
passes out of the body, these unwanted substance are carried right along.
     However, when the kidney is not properly doing its job, these undesirable
chemicals are not removed from the blood, and when blood is examined, a higher
amount than normal is detected.  However, the presence of these additional
quantities do not tell us just what is ailing the kidney, merely that all the
waste has not been removed.  It takes some additional testing of both urine
and blood, as well as special x-ray techniques to narrow down the range of
possible causes, until finally a diagnosis can be made, and treatment started.
     But you're a long way from there at present.  The chances are very much
in your favor, since the result of this original screening is still in normal
range, that a repeat test will show a lower level of BUN.  At the same time
additional tests such as creatinine may reveal that, after all, your brother's
kidneys are still working as they should.

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The material contained here is "FOR INFORMATION ONLY" and should not replace
the counsel and advice of your personal physician.  Promptly consulting your
doctor is the best path to a quick and successful resolution of any medical
problem.