Which laboratory test is primarily used to assess kidney function?

The test primarily used to assess kidney function is creatinine measurement. Creatinine is a waste product that results from the normal breakdown of muscle tissue and is produced at a relatively constant rate by the body. It is eliminated from the body through the kidneys, so measuring the level of creatinine in the blood can provide important information about how well the kidneys are functioning. Elevated levels of creatinine indicate that the kidneys are not filtering effectively, suggesting impairment in kidney function.

In addition to creatinine, other tests such as BUN (blood urea nitrogen) also provide insights into kidney function, but creatinine is often considered more specific to kidney health. Glucose levels are related to metabolic processes, and while they can indicate conditions like diabetes, they do not directly assess kidney function. Electrolyte tests measure levels of minerals in the blood, which can be affected by kidney function but are not diagnostic of it on their own. Thus, creatinine is recognized as the primary test for evaluating kidney function.