Urine Albumin

Sample 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 over the course of a week.
   1. Stable at room temperature for up to 2 days and 8 °C for up to 14 days.

Indications for Urine Albumin and  microalbuminuria.

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

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 diet or high salt.

Pathophysiology of Urine Albumin

1. Details are discussed in urinary proteins.
2. The Persistent proteinuria detected by routine screening method indicates urinary albumin excretion of ≥200 µg/min. This indicates diabetic nephropathy.
3. The level of albumin is not detected by the routine methods 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:

Definition of microalbuminuria:

1. Microalbuminuria is defined as when proteinuria by ordinary methods is not detected.
2. 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.

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 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. So the presence of proteinuria indicates the result of increased permeability of the glomerulus or decreased reabsorption by the renal tubules.
6. The following diagram gives an idea about the kidney’s role in the excretion of protein.

NORMAL protein and albuminSource 1

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

Proteinuria may be classified as protein excreted per 24 hours (day).

Severity  of proteinuria	Proteinuria gram/day
Mild	<1
Moderate	1 to 3
Severe	>3

Microalbuminuria

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

Causes of microalbuminuria:

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

The normal urine picture:

• • Physical features	Chemical features	Microscopic findings
    Color = Pale yellow or amber Appearance = Clear to slightly hazy pH = 4.5 to 8.0 Specific gravity = 1.015 to 1.025	Blood = Negative Glucose = Negative Ketones= Negative Protein = Negative Bilirubin = Negative Urobilinogen = Negative (±) Leucocyte esterase = Negative Nitrite for bacteria = Negative	RBCs = Rare or Negative WBC = Rare or Negative Epithelial cells = Few Cast = Negative (Occasional hyaline) Crystal = Negative (Depends upon the pH of the urine) Bacteria = NegativePlease see more details on the urinary protein. Normal urine picture:

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