chap 6: physical examination of urine

• Clarity


  Ability to see through a liquid
• Hypersthenuric


  Urine with high specific gravity
• Hyposthenuric


  Urine with low specific gravity
• Isosthenuric


  Urine with normal specific gravity
• Refractive index


  Measure of the bending of light as it passes through a liquid
• Refractometry


  Technique for measuring refractive index
• Specific gravity


  Ratio of the density of a liquid to the density of water
• Urobilin


  Orange-brown pigment in urine
• Urochrome


  Yellow pigment in urine
• Uroerythrin


  Pink pigment in urine
• Physical Examination of Urine


  1. Determine urine color

  2. Determine urine clarity

  3. Determine urine specific gravity
• The physical examination of urine includes the determination of the urine color, clarity, and specific gravity
• Early physicians based many medical decisions on the color and clarity of urine
• Observation of urine color, clarity, and specific gravity provides preliminary information concerning disorders
• The results of the physical portion of the urinalysis can be used to confirm or to explain findings in the chemical and microscopic areas of urinalysis
• Normal urine color


  • Colorless
  • Pale yellow
  • Yellow
  • Dark yellow
• Urochrome


  Pigment that causes the yellow color of normal urine
• Urochrome is a product of endogenous metabolism, and under normal conditions, the body produces it at a constant rate
• The intensity of the yellow color in a fresh urine specimen can give a rough estimate of urine concentration
• Other pigments in urine


  • Uroerythrin
  • Urobilin
• Uroerythrin is a pink pigment that is most evident in specimens that have been refrigerated
• Urobilin is an orange-brown pigment that imparts color to urine that is not fresh
• Abnormal urine colors


  • Dark yellow/amber/orange
  • Red/pink/brown
  • Brown/black
  • Blue/green
• Dark yellow/amber/orange urine


  May indicate the presence of bilirubin
• Yellow foam when shaking the specimen indicates the presence of bilirubin
• Photo-oxidation of bilirubin produces a yellow-green color due to the presence of biliverdin
• Phenazopyridine and azo-gantrisin compounds can cause a yellow-orange urine color
• Phenazopyridine also produces yellow foam when shaking the specimen
• Medications that can cause orange urine


  • Anti-inflammatory drug sulfasalazine
  • Laxatives
  • Chemotherapy drugs
• Causes of red/pink/brown urine


  • Red blood cells
  • Hemoglobin
  • Myoglobin
  • Porphyrins
• Urine containing intact red blood cells is red and cloudy, while urine containing hemoglobin or myoglobin is red and clear
• Menstrual contamination and ingestion of certain foods and medications can also cause red urine
• Causes of brown/black urine


  • Melanin
  • Homogentisic acid (alkaptonuria)
• Medications that can cause brown/black urine


  • Antimalarial drugs
  • Levodopa
  • Methyldopa
  • Phenol derivatives
  • Metronidazole
  • Nitrofurantoin
  • Laxatives
  • Methocarbamol
• Liver and kidney disorders and muscle injury can also result in dark-brown urine
• Ingesting large amounts of fava beans, rhubarb, or aloe can cause a nonpathogenic dark-brown (cola-colored) urine
• Causes of blue/green urine


  • Pseudomonas infection
  • Increased urinary indican
  • Familial benign hypercalcemia
  • Breath deodorizers
  • B vitamins
  • Asparagus
  • Methocarbamol
  • Methylene blue
  • Indomethacin
  • Amitriptyline
  • Propofol
• Dark-brown urine


  Can result from extreme exercise
• Nonpathogenic causes of dark-brown (cola-colored) urine


  Ingesting large amounts of fava beans, rhubarb, or aloe
• Blue/Green urine


  Pathogenic causes are limited to bacterial infections, including urinary tract infection by Pseudomonas species, and intestinal tract infections, resulting in increased urinary indican. A familial benign hypercalcemia, a rare inherited disorder, is sometimes called "blue diaper syndrome" because children with the disorder will have blue urine.