The 2001 Bethesda system.

The Bethesda system is a system of terminology for reporting the results of cervical cytology. It was developed in 1988, and is now widely used in the United States. This system was updated in April 2001. The most important modifications are the following: a) elimination of the category "satisfactory but limited by", b) the reintegration of benign modifications in the normal category, c) "atypical squamous cells of undetermined significance" is now named "atypical squamous cells" and subdivided into "atypical squamous cells of undetermined significance" and "cannot exclude high grade squamous intraepithelial lesion"; and d) endocervical adenocarcinoma in situ which is now a separate entity. Low grade squamous intraepithelial lesions and high grade squamous intraepithelial cells remain unchanged. Recommendations have been proposed concerning automated review and ancillary testing. This paper is available too at: http://www.insp.mx/salud/index.html.