Physical Properties of Urine

• URINE COLOR

  • The normal urine color includes pale yellow- yellow- dark yellow
  • The yellow color of urine is caused by the presence of pigment, UROCHROME
  • The actual amount of UROCHROME produced on the body is dependent on the body's metabolic state
  • Increased urochrome production: [OFT]
  • Thyroid conditions
  • Fasting 
  • Urine stands at room temperature (Old spx)
• Two additional pigments present in urine in much smaller quantities:

  • Uroerythrin - pink pigment, most evident in specimens that have been refrigerated, resulting in the precipitation of amorphous rates.
  • Urobilin - orange brown color, an oxidation product of the normal urinary constituent urobilinogen.

  The concentration of a normal urine specimen can be estimated by urine Color
• How to Check for Urine Color

  Care should be taken to examine the specimen under a good light source, looking down through the contalner against a white background
• Urine Color: Colorless

  • Causes: Recent fluid intake
  • Clin. correlation: Seen in random specimens
• Urine Color: Pale yellow

  • Causes: 
  • Polyuria or Diabetes Insipidus
  • Diabetes mellitus
  • Dilute random specimen
  • Clin. correlation:
  • Increased 24 hours volume and low specific gravity
  • Elevated specific gravity and positive glucose test result
• Urine Color: Bright Yellow

  • Causes: Riboflavin (vitamin B12)
  • Clin. correlation: multivitamins
• Urine Color: Dark Yellow

  • Causes: 
  • Concentrated specimen
  • Dehydration
  • Acriflavine
  • Carotene (may cause orange urine)
  • Nitrofurantoin
  • Clin. correlation:
  • After strenuous exercise or first morning specimen
  • Fever or burns
  • For acriflavine, negative bile test results and possible green fluorescence
  • High consumption of vegetables and fruits that contain carotene
  • Antibiotic administered for urinary tract infections
• Urine Color: Amber/Orange

  • Causes:
  • Bilirubin
  • Warfarin / Coumadin
  • Clin. correlation:
  • Yellow foam when shaken and positive chemical test for bilirubin
  • Anticoagulant
• Urine Color: Orange-yellow

  • Causes:
  • Phenazopyridine (Pyridium)
  • Phenindione
  • Clin. correlation:
  • Drug commonly administered for urinary tract infection, produces also a yellow foam when shaken
  • Anticoagulant, orange in alkaline urine and colorless in acid urine
• Urine Color: Yellow-green

  • Causes: Bilirubin oxidized to biliverdin
  • Clin. correlation: Colored foam in acidic urine and false negative test results for bilirubin
• Urine Color: Green

  • Causes: Pseudomonas infection
  • Clin. correlation: Positive urine culture
• Urine Color: Blue-green

  • Causes:
  • Amitriptyline
  • Methocarbamol (Robaxin)
  • Methylene blue
  • Phenol
  • Clorets
  • Indican
  • Clin. correlation:
  • Antidepressant (blue urine color)
  • Muscle relaxant (blue urine color)
  • Fistulas
  • When oxidized (green urine color)
  • Mouth deodorant (green urine color)
  • Bacterial infection, intestinal disorders
• Urine Color: Red

  • Causes:
  • RBCs
  • Hemoglobin
  • Myoglobin
  • Beets
  • Rifampin
  • Menstrual contamination
  • Clin. correlation:
  • Cloudy urine with positive chemical results for blood and visible RBCS when viewed on the microscope
  • For hemoglobin, clear urine with positive chemical test for blood; due to intravascular hemolysis
  • Clear urine with positive chemical test for blood; muscle damage
  • Alkaline urine of genetically susceptible person
  • Medication for Tuberculosis
  • Cloudy specimen with RBCs, mucus, and clots
• Urine Color: Red-brown

  • Causes:
  • RBCs oxidized to methemoglobin
  • Fuchsin, aniline dye
  • Myoglobin (25 mg/di)
  • Clin. correlation:
  • Seen in acidic urine after standing; positive chemical test for blood
  • Foods, candy
• Urine Color: Port wine / Burgundy red

  • Causes: Porphyrins/ Porphyria
  • Clin. correlation:
  • Negative test for blood, may require additional testing
  • Maybe colorless in Lead poisoning
• Urine Color: brown

  • Causes: Homogentisic acid (Alkaptonuria)
  • Clin. correlation: Seen in alkaline urine after standing
• Urine Color: black

  • Causes:
  • Melanin or Melanogen, Malignant melanoma
  • Argyrol (anti-septic)
  • Methyldopa or Levodopa
  • Metronidazole (Flagyl)
  • Phenol derivatives
  • Clin. correlation:
  • Urine darkens on standing and reacts with nitroprusside and ferric chloride
  • Color disappears with ferric chloride
  • Antihypertensive drug
  • Darkens on standing, for parasitic infection interfere with copper reduction tests
• purple staining may occur in catheter bags and is caused by Indicant in the urine or a bacterial infection, frequenty caused by Klebsiella or Providencia species.
• Cola-colored urine - associated with rhabdomyolysis and in some patients taking L-Dopa
• Urine foam

  • If a normal urine specimen is shaken or agitated sufficientily, a foam can be forced to develop at Its surface that readily dissipates on standing
  • Yellow foam - due to bilirubin and phenazopyridine / pyridium
  • White foam - due to protein mainly albumin / protein
• URINE CLARITY

  • Clarity is a general term that refers to the " Transparency or Turbidity " of a urine specimen
  • The specimen should be in a clear container
  • The clarity of a urine specimen certainly provides a key to the microscopic examination results, because the amount of turbidity should correspond with the amount of material observed under the microscope
  • Clear urine is not always normal.
  • Nubecula = Faint cloud in urine after standing due to WBCs, epithelial cells and mucus
• How to Check for Urine Clarity 

  Usually examining the Mixed specimen while holding it in front of a light source. View through a newspaper print.
• Urine clarity Report

  • Clear - no visible particulates, transparent
  • Possible cause: all solutes present are soluble (such as glucose and proteins)
• Urine clarity Report

  • Hazy - few particulates, print easily seen through urine
  • Possible cause: RBC & WBC (varies with the substance and amount present)
• Urine clarity Report

  • Cloudy - many particulates, print blurred through urine
  • Possible cause: crystals, microbes, fat (lipids, chyle), epithelial cells
• Urine clarity Report

  • Turbid - print cannot be seen through urine
  • Possible cause: mucus, mucin, pus, radiographic dye, semen, contaminants
• Urine clarity Report

  • Milky - may precipitate or be clotted
  • Possible cause: Fats or lymph (lipiduria and chyluria)
• Non-Pathologic Causes of Urine Turbidity

  • Squamous epithelial cells
  • Mucus
  • Amorphous phosphates, carbonates, rates
  • Semen, spermatozoa
  • fecal contamination
  • Radiographic contrast media
  • Talcum powder
  • Vaginal creams
• Pathologic Causes of Urine Turbidity

  • RBCs
  • WBCs
  • Bacteria
  • Yeast
  • Non-squamous epithelial cell
  • Abnormality crystals
  • Lymph fluid
  • Lipids
• LAB CORRELATION IN URINE TURBIDITY

  • Acidic urine: Amorphous urates, radiographic contrast media
  • Alkaline urine: Amorphous phosphates, carbonates
  • Soluble with heat: Amorphous urates, uric acid crystals
  • Soluble in dilute acetic acid: RBCs, Amorphous phosphates, carbonates [SaRAP Carbonarra]
  • Insoluble in dilute acetic acid: WBCs, Bacteria, yeast, spermatozoa
  • Soluble in Ether: Lipids, lymphatic fluid chyle
• For checking of color - Check urine with a white background with a good light source

  For checking of clarity - Check urine with a mixed urine specimen with a good light source; not a first choice: view on newspaper print

  For checking of both clarity and color - Check urine with a white background with a good light source
• URINE ODOR


  Seldom of clinical sianificance and is not a part of the routine urinalysis
• • Aromatic - Normal / Redolent / Fragrant / odorous
  • Foul, ammonia-like, fetid / Putrid - Bacterial decomposition, urinary tract infection, old urine
  • Fruity, sweet - Ketones, DM, Starvation, vomiting, strenuous exercise, diarrhea
  • Maple syrup - Maple syrup urine disease, caramel sugar
  • Mousy odor, Barny or musty odor - Phenylketonuria
  • Rancid - Tyrosinemia
  • Sweaty feet - Isovaleric academia
  • Cabbage, Hops - Methionine malabsorption (related to homocystinuria)
• • Bleach - contamination
  • Odorless - Acute tubular necrosis
  • Rotting fish / galunggong odor - Trimetylaminuria
  • Pungent or distinctive odor - Asparagus, Garlic, Onion ingestion, UTI(Brunzel), bacteruria, increase urinary amines
  • Swimming pool - Hawkinsinuria
  • Sulfur odor or rotten egg - Cystinuria
  • Menthol-like - Phenol-containing medications
  • Mercaptan odor - Asparagus, garlic, and egg
• URINE SPECIFIC GRAVITY

  • Specific gravity is defined as the density of a solution compared with the density of a similar volume of distilled water (S.G 1.000) at a similar temperature
  • Specific gravity is influenced by the number of particles present, and the size of the particles.
  • The evaluation of urine concentration is included in the routine urinalysis by measuring the specific gravity
• • The specific gravity of the plasma filtrate entering the glomerulus is 1.010
  • Isosthenuric- term to describe urine with S.G 1.010
  • Hyposthenuric / Diluted urine - term to describe urine with S.G below 1.010 (presence of  swollen RBC / glitter cell)
  • Hypersthenuric / Concentrated urine- term to describe urine with S.G above 1.010 (presence of crenated RBC)
• • S.G of Normal random urine: 1.002 to 1.035
  • Most of the random specimen falls between 1.015 - 1.030
  • Abnormally high S.G results- above 1.040 - are seen in patients who have recently undergone an intravenous pyelogram (E.g., Radiographic contrast dye / X-ray film, Dextran, and other Plasma expanders)
• CLINICAL SIGNIFICANCE OF URINE SPECIFIC GRAVITY RESULTS (Brunzel, 3rd ed.)

  • 1.000 - Physiologically impossible-same as pure water: suspect adulteration of urine specimen
  • 1.001-1.009 - Dilute urine; associated with increased water intake or water duresis (e.g., diuretics, Diabetes insipidus, inadequate secretion/action of ADH)
  • 1.010 to 1.025 - Indicates average solute and water intake and excretion
• CLINICAL SIGNIFICANCE OF URINE SPECIFIC GRAVITY RESULTS (Brunzel, 3rd ed.)

  • 1.025 to 1.035 - Concentrated urine; associated with dehydration, fluid restriction, profuse sweating, osmotic
  • > 1.040 - Physiologically impossible; indicates presence of iatrogenic substance (e.g., radiographic contrast media, mannitol)
• METHODS FOR DETECTION URINE S.G

  • Direct methods - Hydrometer, Harmonic oscillation densitometry, falling drop
  • Indirect methods - Refractometer, reagent strip