Microalbuminuria is important to detect in patients with diabetes mellitus, as its presence indicates a high risk for developing nephrotic range proteinuria, end-stage renal failure and other diabetic complications.


Testing is typically performed on a 24 hour urine. It uses a more sensitive and accurate technique for quantitating albumin, such as radioimmunoassay, immunonephelometry, or accelerated immunoturbidity.


urinary albumin excretion in µg/min =

= (mg/dL albumin in 24 hour urine) * (volume of 24 hour urine in dL) / 1440



• 1440 is the number of minutes in a day



• Albumin excretion in the urine is usually 2-12 µg/min, with values below 20 µg/min considered normal.

• Microalbuminuria is defined as urinary albumin excretion rate of 20-200 µg/min in 2 of 3 samples collected over a 6 month period.

• Urinary albumin excretion > 200 µg/min is considered overt proteinuria.

24 hour urine albumin in mg per 24 hours

24 hour urine albumin in µg/min


< 30 mg per 24 hours

< 20 µg/min


30 – 299 mg per 24 hours

20 – 199 µg/min


>= 300 mg per 24 hours

>= 200 µg/min

clinical albuminuria



• The test may not be interpreted correctly in the presence of confounding factors, including: urinary tract infection, fever, uncontrolled hyperglycemia, uncontrolled hypertension, and congestive heart failure.

• Proper specimen collection and accurate testing are required for meaningful results.


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