Urinalysis

• Color of urine

  Varies from almost colorless to black, due to normal metabolic functions, physical activity, ingested materials or pathologic conditions
• Normal urine color


  • Pale yellow
  • Yellow
  • Dark yellow
  • Amber
• Yellow color of urine

  Caused by the presence of a pigment called urochrome
• Care should be taken to examine the specimen under a good light source, looking down through the container against a white background
• Abnormal urine colors


  • Dark yellow or amber - presence of the abnormal pigment bilirubin
  • Yellow-orange - administration of phenazopyridine (Pyridium) or azo-gantrisin compounds
  • Red - presence of blood
  • Brown urine containing blood - glomerular bleeding
  • Brown or black - melanin, homogentisic acid, levodopa, methyldopa, phenol derivatives, and metronidazole
  • Green
  • Blue/green - bacterial infections, including urinary tract infection by Pseudomonas species and intestinal tract infections resulting in increased urinary indican
• Causes of urine color

  • Colorless - Recent fluid consumption, Polyuria or diabetes insipidus, Diabetes mellitus
  • Pale yellow - Dilute random specimen
  • Dark yellow - Concentrated specimen, D complex vitamins, Dehydration, Bilirubin, Acriflavine, Narofurantoin, Phenazopyridine (Pyridium), Phenindione
  • Orange-yellow - Bilirubin oxidized to biliverdin
  • Yellow-green - Pseudomonas infection
  • Green - Amitriptyline
  • Blue-green - Methocarbamol (Robaxin), Clorets, Phenol
  • Pink - RBCs
  • Red - Hemoglobin
  • Port wine - Myoglobin
  • Red-brown - Beets, Rifampin
  • Brown - Menstrual contamination, Porphyrins, RBCs oxidized to methemoglobin, Myoglobin
  • Black - Homogentisic acid (alkaptonuria), Malignant melanoma, Melanin or melanogen, Phenol derivatives, Argyrol (antiseptic), Methyldopa or levodopa, Metronidazole (Flagyl)
• Clarity of urine


  Refers to the transparency or turbidity of a urine specimen
• Terms used to report urine clarity

  • Clear - No visible particulates, transparent
  • Hazy - Few particulates, print easily seen through
  • Cloudy - Many particulates, print blurred through
  • Turbid - Print cannot be seen through urine
  • Milky - May precipitate or be clotted
• Color and clarity procedure

  1. Use a well-mixed specimen

  2. View through a clear container

  3. View against a white background

  4. Maintain adequate room lighting

  5. Evaluate a consistent volume of specimen

  6. Determine color and clarity
• Urine odor


  Freshly voided urine has a faint aromatic odor. Unusual odors can be caused by bacterial infections (strong unpleasant ammonia-like odor) or diabetic ketones (sweet or fruity odor).
• Causes of unusual urine odors

  • Bacterial decomposition, urinary tract infection - Foul, ammonia-like
  • Ketones (diabetes mellitus, starvation, vomiting) - Fruity, sweet
  • Maple syrup urine disease - Maple syrup
  • Phenylketonuria - Mousy
  • Tyrosinemia - Rancid
  • Isovaleric acidemia - Sweaty feet
  • Methionine malabsorption - Cabbage
  • Contamination - Bleach
• Reagent strips


  Chemical-impregnated absorbent pads attached to a plastic strip that undergo color-producing chemical reactions when in contact with urine, allowing analysis of pH, protein, glucose, ketones, blood, bilirubin, urobilinogen, nitrite, leukocytes, and specific gravity
• Care of reagent strips

  1. Store with desiccant in an opaque, tightly closed container

  2. Store below 30 degrees Celsius, do not freeze

  3. Do not expose to volatile fumes

  4. Do not use past the expiration date

  5. Do not use if chemical pads become discolored

  6. Remove strips immediately prior to use
• Reagent strips must be checked with both positive and negative controls a minimum of once every 24 hours