Felis ISSN 2398-2950

Effusion: overview

Contributor(s): Kathleen P Freeman, Kim Willoughby

Overview

  • Pleural, pericardial and peritoneal cavities normally contain only a small amount of fluid, little or no fluid can be obtained by aspiration unless effusion is present.
  • Effusion is the presence of excess fluid in a body cavity:
  • Investigation of effusions commonly includes fluid analysis (RBC, nucleated cell counts, and refractometer total protein) and cytology.
  • Additional biochemical analyses may be of benefit for further characterization.

Sampling

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Tests

Methodologies

  • Direct smear of drop as for blood smear.
  • For fluids of low cellularity:
    • Centrifuge at 100 rpm for 10 min.
    • Cytocentrifuge preparations or other special methods for concentration may be available at some commercial laboratories.
    • Pour off supernatant (care should be taken to observe specimen during pour-off since viscous fluid may result in loss of sediment).
    • Flick tube to resuspend sediment.
    • Put 1 drop onto slide.
    • Make smear as for blood or pull apart/squash method using two slides.
  • Romanowsky-type stains most commonly used for cytologic evaluation.

Availability

  • Standard laboratory procedure.

Validity

Sensitivity

  • As with any cytologic specimens, absence of evidence does not provide conclusive support for absence of a particular condition.

Specificity

  • As with any cytologic specimens, absence of evidence does not provide conclusive support for absence of a particular condition.

Technique (intrinsic) limitations

  • Cytologic evaluation may be compromized by excessive blood contamination.

Result Data

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Further Reading

Publications

Refereed papers

  • Recent references from VetMed Resource and PubMed.
  • Meyer J D & Franks P T (1987) Effusion - classification and cytologic examination. Comp Cont Educ Pract Vet 9, 123-128.

Other sources of information

  • Cowell R L, Tyler R D & Meinkoth J H (1999) Diagnostic Cytology and Hematology of the Dog and Cat. 2nd edn. St. Louis: Mosby.
  • Duncan J R, Prasse K W & Mahaffey E A (1994) Veterinary Laboratory Medicine. In: Clinical Pathology. 3rd edn. Iowa State University Press.


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