Which laboratory test is primarily used to assess kidney function?

The assessment of kidney function is primarily accomplished through the measurement of serum creatinine and blood urea nitrogen (BUN) levels. Creatinine is a waste product generated from muscle metabolism and is normally filtered out of the blood by the kidneys. Elevated levels of serum creatinine indicate that the kidneys are not functioning effectively. Similarly, BUN levels reflect the amount of nitrogen in the blood that comes from urea, which is also filtered by the kidneys. High BUN levels can signal impaired renal function as well.

While other tests like the complete blood count, liver function tests, and electrolyte panels provide valuable information about general health and other organ functions, they do not specifically evaluate kidney function. For instance, a CBC focuses on blood cells and can reveal issues like anemia or infection, while liver function tests assess liver health. An electrolyte panel measures the levels of essential minerals, which may indicate kidney issues indirectly but does not provide a direct assessment like serum creatinine and BUN do. This make serum creatinine and BUN the primary tests for assessing kidney function.