Cervix - Cytology
Papanicolaou (Pap) stain

Topic Completed: 1 June 2011

Revised: 20 December 2018, last major update June 2011

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Cite this page: Pernick N. Papanicolaou (Pap) stain. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/cervixcytologypap.html. Accessed February 18th, 2019.
Definition / general
  • Multichromatic staining histological technique developed by George Papanikolaou
  • Classic form involves five dyes in three solutions (IHC World, Wikipedia)
  • An alcohol dried preparation that produces better nuclear detail than air fixation
  • Stains ribosomes blue green, particularly in parabasal cells, mesothelial cells and metaplastic squamous cells
  • Stains metabolically inactive cells pink, such as superficial cells
  • Stains keratinized cells or thick specimens orange (benign or malignant)
  • Must fix smear quickly and stain carefully; air dried smears are inadequate
Clinical images

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Smearing and slide preparation

Procedure for staining

Cytology images

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smears - examples
of good cellularity