Cytology: fine needle aspirate
Synonym(s): FNA
Overview
- Microscopic study of cells obtained from skin, abnormal masses or internal organs.
- Cells are smeared onto a slide and stained, then viewed by light microscopy.
- Rapid, requires minimal equipment.
- Direct evaluation of neoplastic or inflammatory changes provided representative sample obtained.
- Failure to obtain a representative sample can give misleading results.
Uses
Alone
- Cutaneous masses.
- Intra-abdominal masses (liver, spleen, kidney, mesenteric lymph node).
- Intra-thoracic masses.
- Intra-operative evaluation of masses.
In combination
- To assess the nature of a mass during surgical excision, prior to histopathology.
- Diagnostic imaging: in assessment of intra-abdominal or thoracic masses.
Sampling
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Tests
Methodologies
- Modified Wright's stain or Giemsa stain: best for inflammatory lesions.
- Diff-quick stain: can adjust color as blue and yellow components are separate; poor nuclear detail.
- New Methylene Blue: good for examination of cell nuclei, bacteria and fungi, yeast and fat globules.
- Light microscopy: scan at x4 and x10; use x50 and x100 for fine detail.
Validity
Sensitivity
- Less sensitive than histopathology because more difficult to obtain representative sample.
Specificity
- Low compared to histopathology as may miss diagnostic cells.
Technique intrinsic limitations
- Information about tissue architecture cannot be obtained.
- May require confirmation by histopathology.
Technician extrinsic limitations
- May be difficult to obtain representative sample.
- Blood contamination of sample can dilute relevant cells.
- Requires some experience to obtain consistently reliable samples.
Result Data
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Further Reading
Publications
Refereed papers
- Recent references from PubMed and VetMedResource.
Other sources of information
- Campbell T W & Ellis C K (2007) Avian and Exotic Hematology and Cytology. 3rd edn. Wiley-Blackwell. ISBN: 978-0813818115.