Which laboratory test assesses kidney function?

The Blood Urea Nitrogen (BUN) test is specifically designed to assess kidney function. This test measures the amount of urea nitrogen in the blood, which is a waste product produced from the metabolism of protein. The kidneys are responsible for filtering urea nitrogen from the bloodstream and excreting it in urine. Elevated levels of BUN can indicate impaired kidney function, as the kidneys are not effectively removing waste from the blood. Therefore, the BUN test is a crucial indicator when evaluating the health of the kidneys and can help diagnose kidney disease or other related conditions.

In contrast, the other tests listed serve different purposes: the Complete Blood Count (CBC) evaluates various components of blood, the Liver Function Test (LFT) focuses on liver health, and Prothrombin Time (PT) assesses blood clotting ability. Each of these tests is important in its own right, but they do not provide specific insights into kidney function like the BUN test does.