what does bun on
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.