A high BUN count usually indicates that the kidneys are not working properly, but there are other issues that can cause high results, as stated by Mayo Clinic. Some other causes for a high BUN count are a high protein diet, dehydration and congestive heart failure.
"BUN" is an acronym for "blood urea nitrogen," and results can vary depending on an individual's age as well as the lab that processes the test, as explained by Mayo Clinic. Shock, severe burns and some medications, such as certain antibiotics, can also cause higher-than-normal BUN results. Doctors consider a BUN test a standard type of blood test and use it to measure the amount of urea nitrogen in the blood.
The liver breaks down proteins in the body, which causes ammonia production, according to Mayo Clinic. The ammonia produced contains nitrogen, which combines with other elements in the body, such as carbon and hydrogen. This is what forms urea, which travels through the bloodstream from the liver to the kidneys. Kidneys that are functioning normally remove urea from the blood, and it leaves the body through the urine. A BUN test measures an individual's level of kidney function by providing an evaluation of urea nitrogen levels.