Which laboratory value assesses kidney function and informs urological evaluation?

• A. Urinalysis Results Only
• B. Blood Urea Nitrogen
• C. Serum Creatinine and Estimated GFR
• D. White Blood Cell Count

Answer: (C)

Assessing kidney function hinges on how well the kidneys filter blood. The most informative measure is serum creatinine together with the estimated GFR. Creatinine is a waste product cleared by filtration, so higher levels indicate reduced filtration. The estimated GFR uses creatinine plus factors like age, sex, and race to estimate how much blood the kidneys can filter each minute. This combination gives a practical, quantitative view of kidney function and directly informs urological evaluation—helping to gauge overall kidney health, assess surgical or contrast-agent risk, and guide disease monitoring.

Urinalysis can reveal infections, blood, protein, or stones, but it doesn’t quantify filtration capacity. BUN is affected by hydration and protein intake and doesn’t consistently reflect kidney function on its own. White blood cell count indicates inflammation or infection and not kidney filtration. That’s why serum creatinine with eGFR is the best choice for assessing kidney function and guiding urological care.