Which test is used to quantify proteinuria after a dipstick indicates nephrotic-range proteinuria?

• A. Urine protein-to-creatinine ratio
• B. Urine osmolality
• C. Serum albumin
• D. Urine sodium

Answer: (A)

When a dipstick shows nephrotic-range proteinuria, you need a quantitative measure of how much protein is being lost in the urine. The urine protein-to-creatinine ratio uses a single random urine sample to estimate daily protein excretion by comparing protein concentration to creatinine. This ratio correlates well with a 24-hour urine collection but is much more convenient, making it the preferred test to quantify proteinuria in this scenario and to track changes over time.

Urine osmolality measures how concentrated the urine is, not the amount of protein. Serum albumin reflects protein levels in the blood, not the urine. Urine sodium assesses sodium loss and volume status, not protein excretion.