Urine Albumin 24 Hours, and Microalbuminuria

What sample is needed for Urine Albumin

1. The patient is directed to collect 24 hours of urine as follows.
   1. Discard the first urine sample.
   2. Then, he/she will collect all the samples for another 24 hours and collect the last sample.
2. Store at 2 to 4 ° C.
3. Use no preservatives.
4. For microalbuminuria, collect random urine (during a week).
   1. Stable at room temperature for up to 2 days and 8 °C for up to 14 days.

What are the indications for Urine Albumin and microalbuminuria?

1. Patient with renal diseases.
2. Patients with diabetes mellitus to rule out diabetic nephropathy.

What are the precautions for Urine Albumin?

1. Avoid collection of urine after rigorous exercise.
2. Avoid in case of a urinary tract infection.
3. Avoid surgery.
4. Avoid in the case of acute illness.
5. Hematuria may interfere with the result.
6. Avoid a high protein or high salt diet.

How will you discuss the pathophysiology of Urine Albumin?

1. Details are discussed in urinary proteins.
2. Persistent proteinuria detected by routine screening indicates urinary albumin excretion of ≥200 µg/min, which indicates diabetic nephropathy.
3. The routine methods do not detect the albumin level when it is 20 to 200 µg/min or 30 to 300 mg/24 hours.
   1. Normally, urine contains <10 mg/dL of the protein.

Microalbuminuria:

How will you define microalbuminuria?

1. Microalbuminuria is defined as when ordinary methods do not detect proteinuria.
2. Microalbuminuria is defined as persistent proteinuria that is below detection by routine reagent strips but greater than normal.
3. Urinary protein excretion is 20 to 200 µg/minute or 30 to 300 mg/24 hours is not detected in the urine by ordinary methods.

How will you discuss the pathophysiology of microalbuminuria?

1. Microalbumin in the urine indicates a transcapillary escape of protein in the urine and is a marker of microvascular disease in diabetics.
2. The strict control of diabetes prevents diabetic nephropathy and retinopathy.
3. Normally, the glomerular membrane allows proteins with a molecular weight of 50,000 to 60,000 or less.
4. Albumin has a molecular weight of 67,000, and some albumin may filter through the glomeruli, but the convoluted tubules reabsorb it.
5. The presence of proteinuria indicates increased glomerulus permeability or decreased reabsorption by the renal tubules.
6. The following diagram explains the kidney’s role in protein excretion.

What is the normal protein and albumin excretion rate?

Total protein/24 hours

• 1 to 14 mg/dL  (10 to 140 mg/L).
• At rest = 50 to 80 mg/day
• After intense exercise = <250 mg/day.

Albumin by the RID method:

• 3.9 to 24.4 mg/day

Albumin by By Turbidim:

• 1 to 14 mg/dL  (10 to 140 mg/L).
• <150 mg/day.
• At rest = 50 to 80 mg/day
• After strenuous exercise = <250 mg/day

Source 4

24 hours of urine Albumin (protein)

• Adult male = 1 to 14 mg/dL (10 to 140 mg/L).
• Adult female = 3 to 10 mg/dL (30 to 100 mg/L).
• Child <10 years = 1 to 10 mg/dL (10 to 100 mg/L).

Another source

How will you classify the proteinuria/24 hours?

Microalbuminuria

• <30 mg/24 hours.
• <20 mg/L (10 hours collection).

What are the causes of microalbuminuria?

1. Diabetic nephropathy.
2. End-stage renal disease.
3. Proliferative retinopathy in type 1 diabetes mellitus.

How would you describe the Albumin/Creatinine ratio?

1. A random urine sample is taken. Better take a morning sample.
2. What is the significance of the Albumin/Creatinine ratio?
   1. It detects diabetic nephropathy.
   2. Advised in hypertension and diabetes mellitus.
   3. The raised level indicates cardiovascular risk.
   4. It is advised to see the progression of the kidney disease.

Questions and answers: