Exotis ISSN 2398-2985

Reptiles

Contact smears / squash preparations

Synonym(s): Touch imprints, Imprint cytology, Impression smears / Compression preparations

Contributor(s): Vetstream Ltd, Lesa Thompson

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Introduction

  • Provides valuable information on the morphological detail of diseased tissue.
  • In general, contact smears are made by imprinting the cut surfaces of the removed masses or tissues or the cellular material obtained from the scraping of an exposed lesion in situ, onto a glass microscope slide.
  • Impression smears can be taken from any moist or greasy skin surface to see inflammatory, neoplastic or other cellular infiltrates, also to look for acantholytic keratinocytes, bacteria and yeasts.
  • They can also be taken from cut surface of a surgical specimen or post mortem specimen.

Uses

  • For obtaining cytologic specimens from solid, semi-solid and mucoid samples or sample pellets obtained by centrifugation:
    • Suspected bacterial or yeast infections.
    • Non-healing wounds.
    • Suspected neoplasia.
  • In some settings it is used as an adjunct or alternative to fine needle aspiration biopsy Fine needle aspiration biopsy, frozen sectioning, and other pathological techniques.

Advantages

  • Samples are easily and quickly taken and will allow immediate differentiation of neoplastic and infective disease in many cases.

Disadvantages

  • Surface bacteria may not be causative as lesions may be contaminated.
  • Most neoplastic lesions will exfoliate cells, however some, eg sarcoma, will not, so results may be erroneously negative.

Requirements

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Preparation

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Procedure

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Further Reading

Publications


Refereed papers

Other sources of information

  • Campbell T W (2015) Cytology Sampling Techniques and Evaluation. In: Exotic Animal Hematology and Cytology. 4th edn. Wiley-Blackwell, USA. pp 345-353.
  • Heard D, Harr K & Wellehan J (2004) Diagnostic Sampling and Laboratory Tests. In: Manual of Reptiles. 2nd edn. Eds: Girling S J & Raiti P. BSAVA, UK. pp 71-86.

Reproduced with permission from Terry W Campbell: Exotic Animal Hematology and Cytology © 2015, published by John Wiley & Sons.


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