What is the threshold for nephrotic-range proteinuria?

• A. Greater than 1 g/day
• B. Greater than 0.3 g/day
• C. Greater than 5 g/day
• D. Greater than 3.5 g/day

Answer: (D)

Nephrotic-range proteinuria is defined by a very large amount of protein lost in the urine, reflecting substantial glomerular leakiness. In adults, this threshold is a daily protein excretion greater than 3.5 grams. Normal protein excretion is much lower (about 150 mg/day or less), so values well above that indicate a nephrotic-range level. This threshold aligns with nephrotic syndrome criteria, which include heavy proteinuria along with hypoalbuminemia, edema, and often hyperlipidemia. Among the options, the 3.5 grams per day cutoff is the standard definition for nephrotic-range proteinuria; 1 g/day and 0.3 g/day are not nephrotic-range, and while 5 g/day is also very high, the established threshold used clinically is >3.5 g/day.