What laboratory test is most useful in assessing kidney function?

The most useful laboratory test for assessing kidney function is serum creatinine. Creatinine is a waste product that is produced from normal muscle metabolism and is filtered out of the blood by the kidneys. When kidney function declines, the level of serum creatinine in the blood increases because the kidneys are less able to eliminate it.

Monitoring serum creatinine levels provides valuable insight into how well the kidneys are functioning. An elevated serum creatinine level can indicate acute or chronic kidney disease, dehydration, or other conditions affecting renal performance.

In contrast, a complete blood count (CBC) primarily assesses overall health and can indicate infections, anemia, or other conditions but does not specifically evaluate kidney function. Liver function tests focus on liver health and do not provide direct information about kidney performance. A coagulation profile assesses blood clotting factors and is not related to kidney function assessment. Hence, serum creatinine is the most specific and relevant test for evaluating kidney function.