Which screening test is commonly used to diagnose kidney disease?

The blood urea nitrogen (BUN) test is commonly used to help diagnose kidney disease because it measures the amount of urea nitrogen in the blood, which is a waste product formed from the breakdown of proteins. Under normal circumstances, healthy kidneys filter urea nitrogen out of the bloodstream and excrete it in urine. Elevated levels of urea nitrogen can indicate that the kidneys are not effectively performing their filtering function, which is a common sign of kidney disease or dysfunction. Therefore, this test is a crucial part of assessing kidney health.

In contrast, other tests listed do not directly assess kidney function. An electrocardiogram evaluates electrical activity of the heart, while a complete blood count assesses overall health and can indicate various conditions but does not provide specific information about kidney health. Magnetic resonance imaging is primarily used for detailed imaging of soft tissues and organs, rather than diagnosing kidney function. Each of these options serves a different purpose, but the BUN test specifically targets kidney function, making it the most relevant choice in this context.