Urine protein 24-hour, Classification of Proteinuria

Urine protein (24-hour)

How will you collect samples for urine protein in 24 hours?

1. Collect a random sample of urine to rule out the presence of protein.
2. 24-hour urine is collected in a sterile container.
   1. Discard the first sample, note the time, and then collect all other samples for 24 hours.
   2. The last time a urine sample is collected in the container.
   3. While collecting the urine, keep the sample in the refrigerator.
3. Add a few ml of HCL into the container.
4. Even if you do not add preservatives, there is no issue; only refrigeration is needed.
5. Centrifuge and adjust to pH 7.0.
   1. Analyze a fresh sample.

What are the precautions for Urine protein 24-hour?

1. Avoid dehydration due to the lack of fluid intake.
2. Avoid the contamination of urine from the vaginal secretions.
3. Not adequate collection during urinary tract infections (UTI).
4. Avoid using contrast media in radiology within the last three days.
5. Avoid strenuous exercise.
6. Avoid emotional stress.
7. Avoid feces contamination.
8. If needed, clean the urethral area.
9. In heavy menses and discharge, postpone the test.
10. The ladies can use a wide-mouth container and transfer the urine into the bottle.
11. Ideally, refrigerate the container or keep it on ice.

What are the indications for Urine protein 24-hour?

1. The presence of protein in urine is an indicator of renal diseases.
2. This may be done to evaluate the edema.
3. It is advised in diabetic patients.
4. It is advised in hypertensive patients to see the kidney damagae.
5. Advised to see the chronic kidney disease progress.
6. Proteinuria is a marker of increased risk for cardiovascular disease.
7. It is advised in autoimmune diseases.

How would you discuss the pathophysiology of Urine protein?

1. The amount of substances excreted in 24 hours in urine by the kidneys is variable, so a random sample will not give the exact result.
2. So, for the protein, electrolytes, and creatinine, a 24-hour urine sample is the answer.
3. Proteins are found in:
   1. Blood.
   2. Urine.
   3. CSF.
   4. Amniotic fluid.
   5. Saliva.
   6. Feces.
4. In a healthy individual with normal renal function, proteins will not be present in the urine, or only traces may be found.
5. Urine protein sources are:
   1. From the blood.
   2. From kidneys.
   3. From the urinary tract.
   4. From the vagina and prostate.

Classification of proteinuria

Classification of proteinuria

How will you classify proteinuria based on the amount of protein excreted in the urine?

What are the types of proteinuria?

1. Proteinuria may be:
   1. Transient proteinuria:
      1. It may be seen temporarily, like in exercise, fever, dehydration, and stress.
   2. Pathological proteinuria:
      1. It indicates kidney disease or systemic disease.
      2. It may be seen in diabetes, hypertension, glomerulonephritis, and kidney diseases.
   3. Tubular damage proteinuria:
      1. Renal tubules fail to reabsorb protein like tubulointerstitial nephritis.
   4. Orthostatic proteinuria:
      1. This proteinuria appears when standing and disappears when lying down.
   5. Overflow proteinuria:
      1. Excess protein appears in the urine, as in the case of multiple myeloma.

What is the mechanism of protein in the urine?

1. Urine is formed by the ultrafiltration of plasma across the glomeruli.
2. Plasma protein with molecular weight >40,000 is retained in the plasma.
3. Normally, the glomerular membrane does not allow protein filtration into the urine because of narrow spaces in the glomerular membrane.
4. In glomerulonephritis, the glomerular membrane is injured, and there are larger spaces from where the protein, particularly albumin (smaller in size), can easily pass in the urine.

Urine protein: Proteinuria etiology

Proteinuria mechanism

5. Albumin is 1/3 of the urinary protein.
   1. Albumin is filtered through the glomeruli very easily compared to plasma globulin.
6. In pathologic conditions, Albumin is abundant.
7. Urine Albumin is used as the protein marker of glomerular permeability.
8. The term proteinuria is often used synonymously with Albuminuria.
9. Protein is the single most important parameter for renal dysfunction.
10. If more than a trace of protein is found in urine, advise 24-hour urinary protein.
11. Mechanisms will include:
    1. Kidney diseases.
    2. Systemic diseases.

What is normal urine protein 24 hours?

Source 1

• 1 to 14 mg/dL
• At rest = 50 to 80 mg/day
• After intense exercise = <250 mg/day

another source

• The normal albumin excretion rate is <20 µg/minute.
  • Or <30 mg/day
• Adult male = 10 to 140 mg /L OR = 1 to 14 mg/dL
  • Adult female = 30 to 100 mg/L OR 3 to 10 mg/dL
• Child <10 years = 10 to 100 mg/L OR 1 to 10 mg/dL.
• < 150 mg/24 hours.
• Qualitative = normally negative.
  • Significant proteinuria is > 300 mg / 24 hours.

How will you diagnose urine protein 24-hour?

1. A 24-hour urine sample is needed.
2. Urine protein assays are sensitive to all types of proteins like albumin, globulins, and Bence-Jones protein.
3. Most assays can detect a minimum of 3 mg/dL of protein in the urine.
4. Urine dipstick is most commonly used. This is most sensitive to albumin.
   1. The dipstick can detect albumin when it is about 18 mg/dL

What are the causes of increased proteinuria?

1. Glomerular diseases : 
   1. Acute and chronic glomerulonephritis.
   2. Nephrotic syndrome.
   3. Polycystic kidney
   4. Amyloidosis.
   5. Autoimmune diseases like SLE.
   6. Diabetes mellitus.
   7. Malignant hypertension.
2. Decreased tubular reabsorption :
   1. Acute and chronic pyelonephritis.
   2. Renal tubular diseases.
   3. Wilson’s disease.
   4. Fanconi’s syndrome.
   5. Interstitial nephritis.
   6. Cystinosis.
3. Other causes are :
   1. Congestive heart failure.
   2. Multiple Myeloma.
   3. Malignant Lymphoma.
   4. Waldenstrom’s macroglobulinemia.
   5. Trauma and stress.
   6. Acute infections like septicemia.
   7. Toxemia of pregnancy.
   8. Hyperthyroidism.
   9. Poisoning from phosphorus, gold, mercury, lead, and phenol.
   10. Drugs like opiates, etc.
   11. Hypertension.
   12. Postural proteinuria.

Questions and answers: