Felis ISSN 2398-2950

Urinalysis: centrifuged sediment

Contributor(s): Kathleen P Freeman, Karen L Gerber

Overview

  • White and red blood cells, casts, crystals, bacteria and neoplastic cells can be seen on microscopic examination in certain diseases of the urinary tract, eg urinary tract infection, urolithiasis, acute renal failure, transitional cell carcinoma, crystalluria.
  • Sediment examination is an essential part of urinalysis.

Sampling

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Tests

Methodologies

  • Centrifuge 5 ml at 500-3000 rpm for 5 minutes.
  • Decant supernatant.
    Either Add 1 drop of sedistain or a supravital stain such as Sternheimer-Malbin Staining techniques: Sternheimer - Malbin stain to the sediment.
    Or Leave 0.5 ml urine in centrifuge tube.
  • Resuspended 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 microscope to improve contrast.
  • Systematically examine entire specimen under the lower power objective, assessing quantity and type of sediment.
  • Examine sediment under the high power objective to identify morphology of elements and to detect bacteria.

Availability

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

Technician (extrinsic) limitations

  • Standardization of approach and techniques used for every analysis results is recommended and allows the technician to develop experience.
  • Experience may be needed for accurate identification of cellular and noncellular elements in urine sediment.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from VetMedResource and PubMed.
  • Sturgess C P, Hesford A, Owen H & Privett R (2001) An investigation into the effects of storage on the diagnosis of crystalluria in cats. JFMS 3, 81-85.
  • Brobst D (1989) Urinalysis and associated laboratory procedures. Vet Clin North Am Small Anim Pract 19(5), 929-949.
  • McCaw D L, Fleming E J & Mikiciuk M G (1989 ) Interpreting the results of urinalysis - a key to diagnosing renal disorders. Vet Med 84(3), 281-286.

Other sources of information

  • Kaneko J J (1997) Clinical Biochemistry of Domestic Animals. 5th edn. Harvey J W & Bruss M L (eds). Academic Press, Boston.
  • Duncan J R, Prasse K W & Mahaffy E A (1994) Veterinary Laboratory Medicine Clinical Pathology. 3rd edn. Iowa University Press, Ames, Iowa.


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