Reproducibility of cervical cytopathology following an intervention by an external quality control laboratory.

BACKGROUND: This study assessed the effects of a continued education program on the agreement between cervical cytopathology exams interpreted by local laboratories and interpretation made by an external quality control laboratory (LabMEQ). METHODS: Overall, 9,798 exams were analyzed between 2007 and 2008, prior to implementation of a continued education program, and 10,028 between 2010 and 2011, following implementation. Continued education consisted of theoretical and practical classes held every two months. The chi-square test and the kappa coefficient were used in the statistical analysis. RESULTS: Following implementation of continued education, the rate of false-negative results, and those leading to delays in clinical management fell in eight laboratories and the rate of false-positive results in five. Agreement between the results reported by the laboratories and the findings of LabMEQ, evaluated according to clinical management, remained excellent in three laboratories (kappa >0.80 and <1.0), went from good (kappa >0.60 and <0.80) to excellent in seven and from excellent to good in two. Agreement regarding the identification of metaplastic epithelium was poor (kappa = 0.25) but progressed to excellent following the implementation of continued education (kappa = 0.950). Agreement between cytopathology results improved significantly following implementation of continued education in cases reported as unsatisfactory (P < 0.001), atypical squamous cells of undetermined significance, cannot exclude high-grade squamous intraepithelial lesion (P < 0.001), low-grade squamous intraepithelial lesion (P < 0.001), and glandular atypia (P < 0.001). CONCLUSION: Continued education contributed towards improving the reproducibility of cervical cytopathology, decreased the rates of false-negative and false-positive results, and reduced delays in clinical management.

External quality control of cervical cytopathology: interlaboratory variability.

OBJECTIVE: To compare the variability of screening tests held at laboratories with the Unit for External Quality Control (UEQC), checking the frequency of cases that were discordant, false-positive, false-negative, unsatisfactory or that had a delay in clinical management and diagnostic agreement. MATERIALS AND METHODS: The study analyzed 10,053 screening tests from January 2007 to December 2008, including all positive cases, all those that fall under unsatisfactory and at least 10% of negative screening tests. The magnitude of the agreement was analyzed using the kappa coefficient. RESULTS: Out of the 10,053 cases analyzed, 7.59% were considered disagreeing, and it was estimated that 1.1% were false-negative. There was a delay in the clinical procedure regarding 2.44% cases. There were 2.82% of cases identified as false-positive and 1.24% as unsatisfactory. The diagnostic agreement was excellent (kappa = 0.81). The agreement of most laboratories concerning screening tests was classified as very good. The agreement of the sample adequacy was reasonable (kappa = 0.30) and the agreement regarding the representation of epithelia was considered excellent. CONCLUSION: Most laboratories showed very good agreement; however, it is worthy of note that to establish the standardization of diagnostic criteria, and enhance the accuracy of screening and improve the quality of cytopathology test results, it is necessary to perform external quality control.