Equis ISSN 2398-2977

Urine: overview

Contributor(s): Annalisa Barrelet

Overview

  • Changes in the chemical and physical characteristics of urine occur in many diseases, eg urinary tract disease   Bladder: cystitis - bacterial  , hepatic disease, hematologic disorders, endocrinopathy, neoplasia    , musculoskeletal disease and hepatic encephalopathy   Gastrointestinal: neoplasia  .
  • Changes in these characteristics can in turn predict disease and form a screening test in any ill animal.
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Sampling

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Tests

Methodologies

Physical appearance
  • Color   Urine: aspirate  .
  • Turbidity   Urine: aspirate  .

Chemical analysis
Equilibriate refrigerated sample to room temperature

  • Centrifuge 5 ml at 500-3000 rpm for 5 min.
  • Determine specific gravity   Urine: specific gravity  by refractometer on the supernatant.
    Dipstick specific gravity does not correlate well with refractometry
  • Perform multitest dipstick analysis on the supernatant, comparing the color change of dipstick with the reference range at the correct time.
  • Rapidly and completely immerse the dipstick and then immediately shake and hold the dipstick level to avoid run off between pads.

Microscopic examination

  • Decant supernatant:
    EitherAdd 1 drop of sedistain or a supravital stain such as Sternheimer-Malbin to the sediment.
    OrLeave 0.5 ml urine in centrifuge tube.
    • Resuspend the sediment by vigorously tapping the centrifuge tube.
    • Transfer one drop of sediment to a microscope slide (via a pipette) and place a coverslip over it.
    • Lower the condenser on the microscope to improve contrast.
    • Systematically examine the entire specimen under the lower power objective, assessing the quantity and type of sediment.
    • Examine the sediment under the high power objective to identify the morphology of the elements (crystals, cells) and to detect bacteria.

Availability

  • Can be performed in-house by most veterinary clinics.
  • All external laboratories.

Technician (extrinsic) limitations

  • A standard systematic approach for every analysis allows the technician to develop experience, and leads to consistent results.

Result Data

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Further Reading


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