Does acetic acid influence the non-dysplastic Pap smear?

Objective: Acetic acid tests are commonly performed for colposcopic evaluation of the cervix. However, it is unclear whether the acetic acid influences normal Papanicolaou (Pap) smear results.

Methods: Patients were routinely seen in our outpatient department between April and May 2009. Two Pap smears were performed in 50 patients. One smear was done before, the other after the acetic acid test. The smears were evaluated by an experienced cytologist. He did not know whether the smear was done with or without acetic acid.

Results: In a normal smear, there was no influence of acetic acid on the cytologic result. In two patients, a smear of Pap III [Bethesda, atypical squamous cells of undetermined significance (ASCUS)] was seen before acetic acid test. This changed to Pap IIID [Bethesda, low-grade squamous epithelial lesions (LSIL)] after acetic acid test.

Conclusions: The acetic acid test does not seem to alter the result of the non-dysplastic smear. In contrast to this, a dysplastic smear seems to be influenced by the acetic acid. This should be evaluated in a further investigation.