What results in an elevated bun level with a normal serum creatinine?

See below: An elevated BUN with normal creatinine occurs most commonly in dehydrated individuals and is not a sign of kidney damage.It may also occur in in certain other conditions like bleeding in the intestines, artificial nutrition intravenously of Amino Acids and use of steroids.

Many causes: Urea is the breakdown product of protein, and even a high-protein diet -- even eating a steak -- will raise it. Being dehydrated, as after a good workout, or (in those who are obviously sick) shock / GI bleeding / heart failure will raise BUN in preference to creatinine. And reference ranges are set so that several % of healthies fall outside. Labs mean nothing by themselves.