Blood Urea Nitrogen (BUN) is a blood test that measures the level of nitrogen in the form of urea in the bloodstream. Urea is a waste product produced when the body breaks down proteins, and the BUN test helps assess how effectively the kidneys are functioning. Elevated BUN levels can indicate potential kidney problems or other health issues, such as dehydration, high protein intake, or certain medications. However, it is important to interpret BUN levels in conjunction with other clinical information as it is not a specific diagnostic test on its own. Doctors use BUN levels as part of a broader assessment to evaluate kidney function and overall health.