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- Colposcopy facts
- What is colposcopy?
- Why is colposcopy done?
- How is colposcopy done?
- What special tests are done during colposcopy?
- Acetic acid wash
- Use of color filters
- Biopsy of the cervix
- Based on the colposcopy results, what is the approach to treating cervical abnormalities?
- Carbon dioxide laser photoablation
- Loop electrosurgical excision procedure
- Cold knife cone biopsy
Quick GuideCervical Cancer Symptoms, Treatment, HPV and Prevention
What special tests are done during colposcopy?
Three special tests are done during colposcopy: acetic acid wash, use of color filters, and sampling (biopsy) of the cervix tissues.
Acetic acid wash
After the cervix is studied with the colposcope, the cervix is washed with a chemical called acetic acid, which is diluted 3% to 5%. The acetic acid (vinegar) washes away mucus and allows abnormal areas to be seen more easily with the colposcope. Moreover, the acetic acid stains the abnormal areas white. The areas that stain white after the acetic acid wash are called "acetowhite lesions." Sometimes, however, normal areas can also stain white, but these areas have vague or faint borders. In contrast, significant abnormalities, such as genital warts, pre-cancers (dysplasia), and cancers, generally produce acetowhite areas with distinct and clear boundaries.
Sometimes staining with a dilute iodine solution (known as Lugol's solution or Schiller's solution) is also performed to further examine for abnormalities. Normal cells will generally take up the iodine stain (and turn brown) in a uniform manner, whereas severe precancers and cancerous areas will not.
Use of color filters
Another aspect of colposcopy involves the use of color filters. The filters help the physician examine tiny blood vessels (capillaries) in the area of the squamocolumnar junction. Blue or green filtered light can cause abnormal capillaries to become more obvious, usually inside an acetowhite area.
Normal capillaries are slender and spaced out evenly. In contrast, abnormal capillaries can appear as red spots (thickened capillaries seen on end) or can produce a pattern resembling hexagonal floor tiles. The worse the cervical disease, the thicker and more widely spaced out are the capillaries. The abnormal capillary pattern ranges from mild, as with pre-cancer (dysplasia), to severe, as with established cancer. Thus, when cancer eventually develops, capillaries take on odd shapes, like punctuation marks.