A Blood Urea Nitrogen (BUN) test measures the amount of urea nitrogen in the blood. Urea is a waste product formed in the liver when the body breaks down proteins. It is then carried through the blood to the kidneys, where it is filtered out and excreted in urine.
This test is commonly used to evaluate kidney function and to monitor patients with kidney disease or those on dialysis. BUN levels are also used to assess hydration status, liver function, and the effects of a high-protein diet. It is often ordered alongside a creatinine test to calculate the BUN-to-creatinine ratio, which helps differentiate between kidney and non-kidney causes of elevated BUN.
