Microscopic

• Formed elements

  • Disintegrate rapidly
• Refrigeration


  • May cause precipitation of amorphous urates & phosphates
• Warming the specimen to 37°C


  • May dissolve some crystals
• Midstream clean-catch


  Minimizes the external contamination of the sediment
• Thoroughly mix the specimen

  Prior to decanting
• Specimen volume

  Between 10 & 15 mL is the standard amount of urine centrifuged in a conical tube
• Frequently used volume

  12 mL
• If obtaining a 12 mL specimen is not possible


  Volume of specimen should be noted on the report form
• Centrifuge

  For 5 minutes at RCF of 400
• Sediment Preparation: Volumes of and mL are frequently

  used

  0.5 and 1.0 mL
• Urine should be ____ rather than

  poured off

  aspirated off
• Sediment is thoroughly resuspended by

  gentle agitation
• Examining the sediment: Minimum of __ fields (hpf & lpf)

  10
• low power scanning of cover slip parameter

  (recommended; for identifying casts)

  Conventional Glass Slide Method
• examine sediments

  under reduced light

  Bright Field Microscopy
• point of reference in focusing

  correct plane (fried egg appearance)

  Epithelial cell
• Manner of reporting: Casts

  Average number per 10 lpf
• Manner of reporting: RBC WBC

  Average number per 10 hpf
• Manner of reporting: squamous epithelial cells

  Rare, few, moderate or many per lpf
• Manner of reporting: transitional epi cells, yeast

  Rare, few, moderate or many per hpf
• Manner of reporting: Renal tubular epithelial cells

  Average number per 10 hpf
• Manner of reporting: oval fat bodies

  Average number per hpf
• Manner of reporting: abnormal crystals

  Average number per lpf
• Urine sediment stain:

  • Delineates structure and contrasting colors of nucleus and cytoplasm
  • Identifies WBCs, epithelial cells, and casts
  • Most commonly used stain
  • Cystal Violet & Safranin O

  Sternheimer-Malbin Stain
• Urine Sediment Stain:

  • Enhances nuclear detail
  • Differentiates WBCs and RTE cells
  • Metachromatic stain

  Toluidine Blue
• Urine Sediment Stain:

  • Lyses RBC and enhances nuclei of WBCs
  • Distinguishes RBCs from WBCs, yeast, oil droplets, and crystals
  • Cannot be used for initial sediment analysis since it will lyse RBCs and produce a false negative results

  2% Acetic Acid
• Urine Sediment Stain:

  • Oil Red O and Sudan III
  • Stains triglycerides and neutral fats orange-red
  • c. Identify lipid-containing cells and casts
  • Cholesterol cannot be stained, but capable of polarization since they produce a Maltese cross pattern

  Lipid Stains
• Urine Sediment Stain

  • Differentiates gram-positive and gram-

  negative bacteria

  gram stain
• Urine Sediment Stain:

  • Methylene blue & Eosin Y
  • Stains eosinophilic granules

  Hansel Stain
• Urine Sediment Stain

  • Stains structures containing iron
  • Identifies presence of hemosiderin (blue

  color) in cells and casts

  Prussian Blue Stain
• Quantitative measure of formed elements in urine

  using hemocytometer; uses a 12-hour urine

  Addis Count
• Addis Count: RBCs

  0-500,000/12-hour ur
• Addis Count: WBCs and ECs

  0-1,800,000/12-hour urine
• Addis Count: Hyaline Casts

  0-5,000/12-hour urine
• For routine urinalysis

  Bright Field Microscopy
• Enhance visualization of elements with

  low refractive indices

  Hyaline casts, mixed cellular casts, mucous

  threads, and Trichomonas

  Phase contrast microscopy
• Identification of cholesterol

  Polarizing Microscopy
• Identification of Treponema pallidum

  (causative agent of syphilis)

  Dark field microscopy
• Visualization of natural fluorescent

  microorganisms or those stained by

  fluorescent dye

  Fluorescence microscopy
• Three-dimensional microscopy image and

  layer by layer imaging of specimen

  interference contrast