Urine history, Urine Composition, Normal Finding, Advantages of Urine Analysis

History of the urine examination

1. The analysis of the urine is actually the beginning of the laboratory medicines.
2. At that time, the physicians checked the urine’s gross appearance, like color, turbidity, odor, and volume.
   

   Urine physical character

3. They were testing the viscosity and even the sweetness. For sweetness, they were observing the attraction of the ants to urine.
   

   Urine sugar test in the old days

4. The modern urine examination includes physical as well as chemical and microscopic examination.
5. Hippocrates wrote a book on urine examination as uroscopy in 5th BC.
6. In 1140 AD, color char was developed, describing the significance of 20 different colors of the urine.
7. Chemical testing progressed after the ant gathering around the diabetic urine.
8. Later on, taste testing was also started.
9. In 1694, Frederick Dekkers discovered the protein, Albuminuria by boiling the urine.
10. Pisse prophets by the Charlatans became the subject of the book published by  Thomas Bryant in 1627.
11. The advent of the microscope in the 17th century led to the examination of urine sediments.
12. Richard Bright, in 1827 made the urine examination a routine for the patients.
13. In 1930 the number and the complexity of urine examination made urine examination impractical.
14. With modern facilities, the urine examination is the routine part of the patient’s doctor’s office visit.
15. Now urine examination is popular due to:
    • Easily available sample.
    • Urine gives many of the body metabolism information.
    • This information from the urine is cheap.
16. The National Committee for clinical laboratory standards (NCCLS) define the urine analysis procedure is reliable, accurate, safe, and cost-effective.

Urine definition

1. Urine is a liquid biopsy obtained without pain or cost to the patient, but it provides a wealth of diagnostic information.
2. Urine is the main source of information from a sick (damaged) kidneys to the physicians.
3. Urine is the fluid excreted through the kidneys, passes through the ureter, and is stored in the urinary bladder. When the urinary bladder is full, then discharged through the urethra.

In a normal healthy person, urine is:

1. Sterile.
2. Clear.
3. Amber color.
4. It is slightly acidic (pH 5 to 6).
5. Specific gravity is 1.024
6. It has a characteristic odor.
7. The daily output is 500 mL.
   1. Anuria when the urine volume is <100 mL/24 hours.
   2. Oliguria when the urine volume is <400 mL/24 hours.
   3. Polyuria when the urine volume is > 2000 mL/24 hours.

Urine Composition

The kidneys continuously form the urine as an ultrafiltrate of the plasma. Reabsorption of the water and filtered substances essential to the body function converts roughly 170,000 mL of filtered plasma to the average daily urine output of 1200 mL.

1. Urine consists of:
   1. Urea. It is produced in the liver by the breakdown of proteins and amino acids.
      1. This is 50% of the dissolved solid substances in the urine.
   2. Organic substances like creatinine and uric acid.
   3. Inorganic substances. The major substance is chloride (CL¯), followed by Na+ and K+.
      1. The dietary intake makes it difficult to decide on the normal level.
   4. Water.
   5. Other substances found are:
      1. Hormones.
      2. Drugs.
      3. Vitamins.
      4. Cells.
      5. Cast.
      6. Crystals
      7. Bacteria.
         

         Urine formation and changes in the kidney

2. Urine constituents depend upon:
   1. Physical activity.
   2. Dietary intake.
   3. Body metabolism.
   4. Endocrine functions.
3. To confirm the urine sample:
   1. Advise urea and creatinine; these are present in high concentrations than any other body fluids and confirm that the specimen is urine.

The Urine analysis includes:

Physical properties include:

1. Color
2. Appearance (opaque or colorless)
3. Odor

Chemical Tests include:

1. pH
2. Specific gravity
3. Protein
4. Glucose
5. Ketones
6. Bilirubin
7. Urobilinogen
8. Blood
9. Nitrite
10. Leukocyte esterase

Microscopic Examination includes:

1. Red blood cells
2. White cells (WBC)
3. Casts
4. Crystals
5. Epithelial cells
6. Bacteria and another microorganism

Normal Urine findings are :

Characteristic	Normal
Appearance	Pale or yellow
Transparency	Clear
Volume	1200 to 2000 ml/24 hours
pH	5 to 7
Specific gravity	1.001 to 1.035
Cast (hyaline)	0 to 5 / HPF
Red blood cells	≤ 3 / HPF
Blood	Negative Rarely 2 to 3 RBCs/HPF
White blood cells	≤2 to 5 HPF Male = 1 to 2 /HPF Female = 0 to 5 /HPF
Squamous epithelial cells	≤ 15 to 20 / HPF
Yeast	Negative
Bacteria	Negative
Protein	Negative
Glucose (Source 4)	Random sample = Negative Qualitative = 0 (negative) 24 hours sample = 1 to 15 mg/dL
Ketones (Source 4)	Urine = Negative
Bilirubin (Source 4)	Negative (o to 0.02 mg/dL)
Urobilinogen (Source 4)	Negative Random sample= ≤1 mg/dL (0 to 4 mg/24 hours) 2-hour sample = <1 mg /2 hours 24- hours sample = 0.5 to 4.0 mg/dL Another source = 0.2 to 4.0 mg/24 hours
Porphyrins	<300 µg/24 hours
Nitrite	Negative
Albumin	10 to 100 mg /24 hours
Amylase	260 to 950 smogi units/24 hours
Protein (Source 4)	Quantitative = negative Urine 24 hours sample Adult male = 1 to 14 mg/dL Adult female = 3 to 10 mg/dL Child <10 years = 1 to 10 mg/dL
Calcium (Source 4)	Normal diet = 100 to 300 mg/24 hours Low-calcium diet = 50 to 150 mg/24 hours (Another source = 0.3 g/24 hours)
Sodium chloride	average 10 g /24 hours Patient with moderate to severe salt depletion = <10 mmol/L or <20 mmol/L /24 hours (Another source = 15.0 g/24 hours)
Sodium (Source 4)	Adult = 40 to 220 meq/24 hours Child = 41 to 115 meq/24 hours
Potassium (Source 4)	Adult = 25 to 125 meq/ 24 hours Child = 10 to 60 meq/24 hours (Another source = 3.3 g/24 hours)
Magnesium (Source 4)	75 to 150 mg/24 hours (Another source = 0.1  g/24 hours)
Bicarbonate	Negative
Creatinine	Male = 20 to 28 mg/Kg/24 hours Female = 15 to 21 mg/Kg/24 hours (Another source = 1.5 g/24 hours) 1.0 to 1.6 gm/24 hours
Creatine	<100 mg/24 hours (higher value in children and pregnancy)
Urea nitrogen	5 to 15 g/24 hours
Nitrogen	7 to 20 g/24 hours
Urea	10 to 35 g/24 hours (Another source = 25.0 to 35.0 g/24 hours)
Uric acid (Source 4)	With normal diet =  250 to 750 mg/24 hours With purine-free diet = <400 mg/24 hours With high-purine diet = <1000 mg/24 hours (Another source = 0.4 to 1.0 g/24 hours)
Chloride (Source 4)	Adult = 110 to 250 meq/24 hours Child  <6 years = 15 to 40 meq/24 hours Child 10 to 16 years = 64 to 176 meq/24 hours
Ammonium NH4+	0.7 g/24 hours
Phosphate PO4¯	2.5 g/24 hours
Lead	<0.08 µg/mL or 120 µg/24 hours
Cystine	Negative  (0)
Homogentisic acid	Negative (0)
δ-aminolevulinic acid	1.3 to 7.0 mg/24 hours
Phenyl pyruvic acid	Negative (0)
Hemoglobin /myoglobin	Negative (0)
Addis count	RBC = up to 1000,000/24 hours WBC + epithelial cells= up to 2000,000/24 hours Casts = up to 100,000/24 hours

 

• Please see the details in Urine analysis Part 2.

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