Equis ISSN 2398-2977

Cytology: fine needle aspirate

Synonym(s): FNA

Contributor(s): Prof Derek Knottenbelt, Rose Raskin, Patricia Rose

Overview

  • Microscopic study of cells obtained from skin, lymph nodes, body fluids/exudates or internal organs.
  • Cells are smeared onto a slide and stained, then viewed by light microscopy.
  • Rapid results.
  • Requires minimal equipment.
  • However, cells in exudates may be difficult to separate/concentrate and stain usefully.
  • Direct evaluation of neoplastic/inflammatory changes provided representative sample obtained.
  • Requires skilled cytopathologists as some apparently neoplastic changes can be "normal".

Sampling

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Tests

Methodologies

Validity

Sensitivity

  • Less sensitive than histopathology because architectural detail is lacking and more difficult to obtain representative sample.
  • More difficult to assess cell types.
  • Requires cytopathologist.

Specificity

  • Low compared to histopathology as may miss diagnostic cells.
  • Good for discrete cell tumors, eg lymphoma, mast cell, squamous cell carcinoma.

Technique (intrinsic) limitations

  • Information about tissue architecture cannot be obtained.
  • Often requires confirmation by histopathology.

Technician (extrinsic) limitations

  • May be difficult to obtain representative sample.
  • Skill required.
  • Fairly low repeatability.

Result Data

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Further Reading

Publications

Other sources of information

  • Cowell R L & Tyler R D (1992)Cytology and Hematology of the Horse.St Louis: Mosby.


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