What is the purpose of the BUN test?

The BUN (Blood Urea Nitrogen) test is primarily used to evaluate kidney function. It measures the amount of urea nitrogen in the blood, which is a waste product formed from the breakdown of protein. Under normal conditions, healthy kidneys filter urea from the blood and excrete it in urine. Therefore, elevated BUN levels can indicate an impaired ability of the kidneys to eliminate this waste, which may suggest kidney dysfunction or disease.

Additionally, this test provides important information regarding renal health by helping to assess how well the kidneys are performing their filtering role. The BUN test can also give insights into hydration status and protein intake, linking it closely to kidney function.

The other answer choices relate to different functions: measuring blood glucose levels assesses metabolic health, assessing liver function pertains to the liver's ability to process substances, and determining electrolyte balance is focused on the regulation of minerals like sodium and potassium. None of these tests measure urea levels or directly indicate kidney performance in the way the BUN test does.