After a woman has had an abnormal cervical/Pap smear it is necessary to examine her cervix with a special binocular microsocope - a colposcope. The woman to be examined sits on a special couch which supports her legs and a speculum is passed to visualise the cervix (just like having a smear).
To identify the site, grade and shape of the abnormal area of cells, the doctor carrying out the colposcopy examination will stain the cervix in the area of the Transformation Zone (TZ).
A solution of acetic acid (which smells like vinegar) is gently wiped on the cervix with a long 'Q' tip. Abnormal dyskaryotic/dysplastic cells will stain white and, as a generalisation, the more dense the white area becomes the higher the grade of abnormality.
A water-based solution of iodine is then gently applied to the rest of the cervix to identify the complete area of abnormality. With iodine, the normal cells stain jet black and the abnormal cells stain yellow.
In most cases there is good correlation between the abnormality suggested by the cervical smear and the appearances seen through the colposcope. In cases of doubt a small biopsy can be taken from the worst looking area for analysis. This is carried out using special biopsy forceps which look like a bird's beak and remove a small fragment of tissue with minimal discomfort.
Women who have an obvious abnormality at colposcopy, or who have a positive biopsy result will proceed to treatment. The most common form of treatment is called LLETZ (Large Loop Excision of the Transformation Zone) in the UK, and LEEP (Loop Electro-Excision Procedure) elsewhere.
Treatment by LLETZ can take place at the end of the colposcopy examination during the same clinic visit. This is called "See and Treat". Alternatively, treatment may be carried out at a separate, later visit.