Which metric is commonly used to quantify albumin loss in urine for CKD assessment?

• A. Blood urea nitrogen
• B. Serum creatinine
• C. Urinary albumin-to-creatinine ratio
• D. Urine protein concentration

Answer: (C)

The key idea is that quantifying albumin loss in CKD relies on a ratio that accounts for how concentrated or dilute the urine is. The urinary albumin-to-creatinine ratio does exactly that: it measures how much albumin is in the urine relative to how much creatinine is excreted, usually reported as mg of albumin per gram of creatinine. This normalization makes the result stable across different hydration states and urine concentrations, so it’s a reliable marker for albuminuria and early kidney damage.

Other options don’t fit as well for this purpose. Blood urea nitrogen and serum creatinine reflect overall kidney function and waste clearance, not the specific amount of albumin being lost in urine. A urine protein concentration measures all proteins in urine and can be influenced by how concentrated the urine is, making it less specific for albuminuria.