What does a Blood Urea Nitrogen (BUN) test measure?

The Blood Urea Nitrogen (BUN) test specifically measures the amount of urea nitrogen in the blood, which is critical for assessing kidney function. Urea is a waste product formed from the breakdown of protein in the body, and nitrogen is a component of urea. The test provides insights into how well the kidneys are working to filter urea out of the bloodstream. Elevated levels of BUN can indicate kidney dysfunction or disease, dehydration, or high protein intake, while low levels could suggest liver disease or malnutrition. Understanding these aspects is essential for diagnosing and monitoring kidney health. Thus, option B accurately describes the purpose of the BUN test.