External quality control for cervical cytology exams performed in the Brazilian Public Health System of Mato Grosso do Sul State - Revista Brasileira de Ginecologia e Obstetrícia

PURPOSE: To evaluate the diagnostic agreement between the cytopathology reports issued by accredited laboratories and those obtained by quality control. METHODS: We calculated the overall agreement and Cohen’s kappa coefficients of a convenience sample of smears selected monthly by the Information System of Cervical Cancer (SISCOLO) for External Quality Control of the 15 laboratories that performed cytopathological PAP tests for the Brazilian Public Health System (SUS) between 2002 and 2011 in Mato Grosso do Sul, a State of the Midwest Region of the country. A comparison of the reliability values (coefficient of concordance and Kappa coefficient) between the initial and final years was computed by the absolute change (delta) and relative percent difference (RPD). RESULTS: There were 15.989 smears sent for rereading, 48.1% of which had a report of normal/benign changes, followed by atypical/low-grade squamous intraepithelial lesions (36.3%), high grade squamous intraepithelial lesion/carcinoma/adenocarcinoma (4.2%), and unsatisfactory (11.4%). The overall correlation coefficient ranged between 0.2 and 1.0, and the median value increased from 0.7 in 2002 to 1 in 2011 (RPD=+36.6%). During the same period, the median values of the Kappa coefficient increased from 0.5 to 0.9 (RPD=+80.8%). CONCLUSIONS: These results emphasize the feasibility of the External Quality Control of cytopathology at the state level and its implementation results in improvement in the diagnoses performed in the SUS network.