In a diabetic patient, the threshold for microalbuminuria is best described as?

• A. Greater than 300 mg/24 h
• B. 30-300 mg/24 h
• C. Less than 15 mg/24 h
• D. Greater than 1500 mg/24 h

Answer: (B)

Microalbuminuria in diabetes is defined by urinary albumin excretion that is above normal but below overt proteinuria. The best description of the threshold is a daily excretion of 30 to 300 mg of albumin. Values under 30 mg/day are considered normal, while values over 300 mg/day indicate macroalbuminuria (overt nephropathy). This range matters because detecting microalbuminuria early signals the onset of diabetic kidney damage and higher cardiovascular risk, prompting earlier intervention such as tighter glycemic and blood pressure control and use of renin–angiotensin system blockers. Since urinary albumin can vary from day to day, testing is usually repeated on separate occasions or assessed as a spot albumin-to-creatinine ratio with a similar threshold to confirm persistent microalbuminuria.