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Atlas of colposcopy – principles and practice

Consumables required for colposcopy

  

The following consumables are required to perform colposcopy and cervical biopsy:
  • gloves (disposable or sterile reusable)
  • cotton swabs, cotton swab sticks
  • normal saline
  • dilute acetic acid (3–5%) solution (freshly prepared)
  • 5% Lugol’s iodine solution
  • Monsel’s solution/paste or silver nitrate
  • 10% formaldehyde solution
  • lubricant jelly.
How does acetic acid help to detect abnormalities on colposcopy?
  • Acetic acid causes reversible coagulation and precipitation of proteins in the epithelial cells. It also draws water out of the cells, causing the cell membrane to collapse around the large abnormal nucleus (if any).
  • Because of these changes, the epithelium, which is normally a transparent filter, becomes opaque and does not allow passage of light through it.
  • The reflected light from the opaque epithelium gives a white colour to the epithelium.
  • In normal squamous epithelium, the cells have very low protein levels, because the cytoplasm is replaced by glycogen and the nuclei are very small or absent. Acetic acid does not have any effect, because there is no protein to coagulate.
  • In neoplastic epithelium, there are many cells with a high protein content because of large nuclei, extra chromatin, and intact cytoplasm. The excess protein gets coagulated with acetic acid and acts as an opaque barrier to the light. The reflected light gives the white appearance.
  • The higher is the grade of neoplasia, the greater is the protein content and the greater is the density of acetowhitening.











































  
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