What laboratory test is typically used to assess kidney function?

• A. Complete blood count (CBC)
• B. Blood urea nitrogen (BUN) and creatinine levels
• C. Liver function tests
• D. Electrolyte panel

Answer: (B)

Blood urea nitrogen (BUN) and creatinine levels are key indicators of kidney function. The kidneys play a crucial role in filtering waste products from the blood, and an elevation in BUN and creatinine levels often signifies impaired kidney function or decreased glomerular filtration rate (GFR).

BUN measures the amount of nitrogen in the blood that comes from the waste product urea, which is produced when proteins are broken down. Meanwhile, creatinine is a waste product produced from muscle metabolism; its levels are fairly constant and depend on muscle mass. Therefore, both BUN and creatinine are commonly measured together to evaluate how well the kidneys are performing their filtering duties.

Other laboratory tests mentioned, such as a complete blood count (CBC) and liver function tests, serve different purposes. A CBC assesses overall health and detects a variety of disorders, including infections and anemia, but does not specifically evaluate kidney function. Liver function tests measure the health of the liver and do not provide information regarding kidney performance. An electrolyte panel is useful in assessing electrolyte balance and related conditions, but it does not serve as a direct measure of kidney function. Thus, BUN and creatinine levels are the preferred tests for assessing how well the kidneys are functioning.