Home / Training / Manuals / Atlas of visual inspection of the cervix with acetic acid for screening, triage, and assessment for treatment

Atlas of visual inspection of the cervix with acetic acid for screening, triage, and assessment for treatment

Filter by language: English / FranÁais / EspaŮol / Русский / українська

Preventing errors in VIA Ė Errors in assessment Ė Errors in assessment of acetowhite areas


Thin acetowhite areas are the most common cause of diagnostic dilemmas and can be associated with various conditions, such as squamous metaplasia, condylomata, healing and regenerating epithelium, and inflammatory conditions. Although the primary aim of any cervical cancer screening test is to detect CIN2 or worse lesions, the criteria used for a positive VIA finding are such that the detection of a large number of CIN1 lesions is unavoidable.

Thin but opaque acetowhite areas that have well-defined regular margins and are located in the TZ and attached to the SCJ indicate the presence of low-grade cervical precancers. However, some of them may have focal high-grade lesions proximal to the SCJ. Such acetowhite areas should be reported as VIA-positive.

A thin acetowhite area around the external os and extending into the endocervical canal may be associated with a high-grade lesion within the canal. Such lesions are also VIA-positive.

Thin acetowhite areas located in the TZ, attached to the SCJ, and with sharp but angular or geographical margins, with or without satellite lesions, are indicative of HPV infections. However, such lesions could coexist with CIN and should be interpreted as VIA-positive.

Sometimes the thin acetowhite areas associated with inflammatory conditions are difficult to distinguish on VIA from those due to low-grade precancers. If such acetowhite areas have well-defined margins and are located within the TZ, they should be categorized as VIA-positive, and the woman should be referred for further evaluation.

Insufficient application of acetic acid and failure to wait for 1 minute before interpretation may lead to a false-negative VIA result.
Well-soaked cotton balls should be used to apply 5% dilute acetic acid liberally, so that the entire cervix is adequately bathed in acetic acid. It is recommended to use a watch to strictly maintain the required 1-minute contact time of acetic acid with the cervix. Insufficient application or less contact time will lead to lesions being missed or appearing less severe than they actually are. Acetic acid solution tends to get diluted if it is not freshly prepared. Use of freshly prepared acetic acid solution is always recommended, to obtain the expected alterations in colour.


Click on the pictures to magnify and display the legends
IARC, 150 Cours Albert Thomas, 69372 Lyon CEDEX 08, France - Tel: +33 (0)4 72 73 84 85 - Fax: +33 (0)4 72 73 85 75
© IARC 2024 - All Rights Reserved.