After illustrating the physical examination of urine sample, This article is to discuss the Chemical examination of urine, which includes:
- Proteins .
- Glucose and ketones .
- Bilirubin and urobilinogen .
Glucose, ketones, Bilirubin and urobilinogen will be discussed in another post , Here , we will focus on Urinary Proteins.
• It is a glycoprotein secreted by the cells of the ascending limb of the loop of Henle called (Tamm Horsfall) + trace of albumin, (normal urine protein = 150-200 mg/24 hr) .
• Slightly higher values up to 300 mg daily may be excreted by adolescents.
2. Mild proteinuria < 3.5gm :
- Nephritic syndrome.
- Tubulointerstitial disease.
- Orthostatic.
- Exercise.
- Febrile albumnuria.
- Excessive RBCs or pus cells may give False albuminuria.
- Congestive heart failure ==> Congested kidney ==> escape of protein through the glomerulus.
2- Random urine samples in which albumin concentration is related to urinary creatinine concentration i.e. albumin/Cr ratio.
3- Dipsticks are available (Cannot detect Bence- Jones proteins)
N.B
• Normal urine contains albumin < 20 mg/L .
- Micro albuminuria = albumin between 20-150 mg/L this is an indicator of early diabetic nephropathy.
• Proteinuria can be classified into :
-Glomerular e.g. glomerulopathies.
- Tubular e.g. Interstitial nephritis.
- Over flow e.g. multiple myeloma (Bence-Jones proteinuria), myoglobinuria.
-Hemodynamic e.g congestive heart failure, fever and exercise .
Read also :
- Urine Analysis Physical examination, interpretation and significance
- Urine analysis | Microscopic examination of urine sample, interpretation of results
- Proteins .
- Glucose and ketones .
- Bilirubin and urobilinogen .
Glucose, ketones, Bilirubin and urobilinogen will be discussed in another post , Here , we will focus on Urinary Proteins.
Urinary Proteins
• Normally, there is a trace of protein.• It is a glycoprotein secreted by the cells of the ascending limb of the loop of Henle called (Tamm Horsfall) + trace of albumin, (normal urine protein = 150-200 mg/24 hr) .
• Slightly higher values up to 300 mg daily may be excreted by adolescents.
Causes of Proteinuria (Albuminuria)
1. Heavy proteinuria > 3.5gm/24 hr urine = Nephrotic syndrome (glomerular Disease).2. Mild proteinuria < 3.5gm :
- Nephritic syndrome.
- Tubulointerstitial disease.
- Orthostatic.
- Exercise.
- Febrile albumnuria.
- Excessive RBCs or pus cells may give False albuminuria.
- Congestive heart failure ==> Congested kidney ==> escape of protein through the glomerulus.
Methods of measurement of Proteinuria
1- Timed 24 hour urinary excretion.2- Random urine samples in which albumin concentration is related to urinary creatinine concentration i.e. albumin/Cr ratio.
3- Dipsticks are available (Cannot detect Bence- Jones proteins)
N.B
• Normal urine contains albumin < 20 mg/L .
- Micro albuminuria = albumin between 20-150 mg/L this is an indicator of early diabetic nephropathy.
• Proteinuria can be classified into :
-Glomerular e.g. glomerulopathies.
- Tubular e.g. Interstitial nephritis.
- Over flow e.g. multiple myeloma (Bence-Jones proteinuria), myoglobinuria.
-Hemodynamic e.g congestive heart failure, fever and exercise .
Read also :
- Urine Analysis Physical examination, interpretation and significance
- Urine analysis | Microscopic examination of urine sample, interpretation of results