Evaluation of Cellular Adequacy in Endometrial Liquid-Based Cytology.

Objective This study evaluated cellular adequacy in endometrial liquid-based cytology (LBC) specimens. Methods In total, 1267 cases were obtained and the rate of unsatisfactory specimen and diagnostic accuracy for malignancy were assessed. If >= 10 cellular clusters composed of <= 30 endometrial cells were found per specimen, then the sample was provisionally considered adequate. Results The unsatisfactory rate (with fewer than 10 clusters) was 15.4%. Diagnostic accuracy in specimens with >= 10 clusters was significantly higher (90.5% vs 36.4%) than that in specimens with fewer than10 clusters. Moreover, the unsatisfactory rate in patients aged >= 60 years was significantly higher (33.8% vs 13.2%) than that in patients younger than 60 years. Although the unsatisfactory rate was decreased, significant differences were not found between cases with fewer than five clusters (22.6%) and fewer than 10 clusters (33.8%) in patients aged >= 60 years. Diagnostic accuracy in cases with five or more clusters was significantly higher (90.3% vs 0%) than that in cases with fewer than five clusters. Conclusions We propose that >= 10 clusters with >= 30 endometrial cells per cluster could be used as a specimen adequacy criterion for endometrial LBC. If >= 10 clusters cannot be found in patients aged >= 60 years, then the use of the alternative criterion of five or more clusters may yield satisfactory specimen adequacy.