Microalbuminuria

Sample

1. The sample is urine.
2. It is better to do three random samples for a week.
3. The urine sample is stable at room temperature for up to 2 days and at 8 °C for up to 14 days.

Indication

• This is advised in a diabetic patient to rule out diabetic nephropathy.

Pathophysiology

1. Microalbumin is a misnomer. This does not refer to any different form of albumin, but instead, there is a small amount of albumin excreted in the urine.
2. This is defined as excretion of 30 – 150  µg/min protein in the urine and not detected by dipsticks, but can be measured by sensitive methods.
   1. If there is increased urinary albumin excretion that is predictive of diabetic nephropathy and also known as microalbuminuria.

3. Normally the small amount is excreted by the glomeruli which are reabsorbed by the tubules.

4. When the disease increases the albumin excreted by the glomeruli is more than reabsorbed by the tubule will lead to microalbuminuria which is not detected by the ordinary methods.
5. This urinary albumin excretion precedes and highly indicative of diabetic nephropathy and is called microalbuminuria.
   1. Early detection of microalbumin may predict end-stage renal nephropathies with Diabetes type 1, (IDDM) patients.
6. This test is useful for the diagnosis of Angiopathic changes in diabetic patients before gross proteinuria is seen.
7. Evidence suggests that lowering of blood pressure and control of hyperglycemia will alter the course of the disease and prevents irreversible nephropathy.
8. Microalbuminuria is the first sign of diabetes complications like:
   1. Diabetic nephropathy.
   2. cardiovascular disease.
   3. hypertension.
9. Diabetic patients with microalbuminuria have 5 to 10 times more chances for cardiovascular mortality, retinopathy, and end-stage kidney.
10. The presence of microalbuminuria in nondiabetic patients is an indicator of lower life expectancy because of hypertension and cardiovascular disease risk.
11. Nondiabetic nephropathies may show microalbuminuria.

Recommendations for microalbuminuria seen in diabetic patients are:

• Diabetic patients should have an annual checkup of microalbuminuria.

Normal

Source 1

• Albumin in urine < 30 mg/24 hours
• Or < 20 mg/day.
• Or < 20 mg/L (urine collected in 10 hours).

Source 2 

• 0.2 to 1.9 mg/dL     

 Abnormal value 

• Albumin > 30 mg/24 hours .
• Or > 20 mg/L (in 10 hours).

limits with various dipsticks:

1. Albusure 2 to 3 mg/dl
2. Micral 1.5 to 2 mg/dl
3. Micro-Burnintest 4 to 8 mg/dl

Microalbuminuria is seen in:

1. Diabetes mellitus.
2. Myoglobinuria.
3. Nephrotoxic drugs.
4. Bence-Jones proteinuria.
5. Hemoglobinuria.
6. Any kind of Nephropathy.
7. Hypertension.
8. Myocardial infarction.
9. Atherosclerosis ( Generalized vascular disease ).
10. Lipid abnormalities.
11. Pre-eclampsia.

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