Microalbuminuria

What sample is needed for Microalbuminuria?

1. The sample is urine.
2. It is better to collect three random samples over 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.

What are the indications for Microalbuminuria?

1. This is advised in a diabetic patient to rule out diabetic nephropathy, even if routine urine tests are negative.
2. Test high-risk patients every 3 to 6 months.
3. Check in hypertensive patients.

What are the precautions for microalbuminuria?

1. Avoid urine after exercise.
2. Avoid prolonged upright posture.
3. Avoid in case of hematuria.
4. Avoid blood-contaminated urine.
5. Avoid in case of genitourinary tract infection.
6. Avoid in case of congestive heart failure.
7. Avoid in case of uncontrolled hyperglycemia or hypertension.
8. Avoid in test tubes with albumin.
9. Avoid in fever.

What are the factors for False-positive microalbuminuria?

1. It can produce false-positive results when urine pH is ≥8.0.
2. When the temperature is >77 °F.
3. When Tamm-Horsfall protein is present in the urine.

How will you define microalbuminuria?

1. Microalbumin is a misnomer. This does not refer to any different form of albumin; instead, a small amount of albumin is excreted in the urine.
2. Microalbuminuria is defined as persistent proteinuria below the detection limit of routine reagent strips but greater than normal.
3. This is defined as the excretion of 30 to 150  µg/min protein in the urine and is not detected by dipsticks but can be measured by sensitive methods.
4. Microalbuminuria is predictive of diabetic nephropathy.

What is the mechanism of microalbuminuria?

1. The kidneys retain albumin in the blood.
2. When the kidney filtering unit (glomeruli) is damaged or stressed for any reason, a small amount of albumin appears in the urine.

How will you discuss the pathophysiology of Diabetic microalbuminuria?

1. Albumin excretion of 20 to 200 µg/minute (30 to 300 mg/24 hours) detected in 2/3 determinations done in the last 6 months.
2. Microalbuminuria may be found in non-diabetic hypertensive patients.
3. The subclinical state of selectively elevated albumin excretion rate is called microalbuminuria.

4. Normally, the glomeruli excrete a small amount, which the tubules reabsorb.

5. As the disease progresses, the glomeruli excrete more albumin than the tubules reabsorb, leading to microalbuminuria, which ordinary methods do not detect.
6. Structural changes in the glomeruli increase glomerular permeability.
7. Increased glomerular permeability increases urinary excretion of proteins like albumin and IgG.
   3. Albumin remains normal in the first 5 years of type 1 diabetes mellitus.
8. This urinary albumin excretion precedes and strongly indicates diabetic nephropathy and is called microalbuminuria.
9. Early detection of microalbuminuria may predict end-stage renal disease in patients with type 1 diabetes mellitus (IDDM).
10. This test helps diagnose angiopathic changes in diabetic patients before gross proteinuria is seen.
11. Evidence suggests that lowering blood pressure and controlling hyperglycemia will alter the disease’s course and prevent irreversible nephropathy.

What is the significance of microalbuminuria?

1. It is the first sign of diabetes complications (Risk factor predictor):
   1. Diabetic nephropathy.
   2. Cardiovascular diseases.
   3. Myocardial infarction.
   4. Hypertension.
   5. Stroke.
   6. Kidney failure.
   7. Death.
2. Diabetic patients with microalbuminuria have 5 to 10 times more chances for cardiovascular mortality, retinopathy, and end-stage kidney.
3. The presence of microalbuminuria in nondiabetic patients is an indicator of lower life expectancy because of hypertension and cardiovascular disease risk.
4. Nondiabetic nephropathies may show microalbuminuria.
5. Microalbuminuria indicates an early stage and risk factors for cardiovascular or renal disease.

What are the recommendations for microalbuminuria in diabetic patients?

1. Diabetic patients should have microalbuminuria checked annually (every 3 to 6 months).
2. if 2 out of 3 measurements are >20 mg/L, start the treatment (intervention).

What are the causes of Microalbuminuria?

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.

What are the complications of microalbuminuria?

1. It shows poor glycemic control.
2. High blood pressure.
3. Development of advanced retinopathy.
4. Development of neuropathy.
5. Advanced nephropathy.
6. Ultimately, renal failure.
7. Increased vascular damage.
8. Risk for cardiovascular disease.

How will you interpret microalbuminuria?

1. Albumin/creatinine ratio >30 mg/g predicts an overnight excretion rate of 30 µg/minute.
2. Albuminuria <0.3 g/day will be detected only by sensitive methods like nephelometry or electrophoresis.

What is the importance of microalbuminuria?

1. It indicates an early sign of renal involvement.
2. Diabetes.
3. High blood pressure.
4. Cardiovascular diseases.

What is normal Albumin in the urine?

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).

What are the limitations of 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

Questions and answers: