Interobserver reproducibility of ThinPrep anal cytology in men who have sex with men

Background Anal cytology is a sensitive and beneficial screening method for detecting anal intraepithelial lesions in high risk populations such as men who have sex with men (MSM) and HIV infected individuals. Methods Two hundred MSM were enrolled between July 2012 and January 2013. Anal specimens were collected for ThinPrep cytology test and HPV DNA test. Consented HIV serology tests were performed. The cytology slides were separately evaluated using the Bethesda 2001 system by two cytopathologists who were blinded to HPV results. Interobserver reproducibility of cytology diagnoses was evaluated by weighted kappa statistics. Consensus diagnoses were given on any disagreement cases. Results The patients’ ages ranged from 18 to 54 years (mean 27.21+SD 7.92). At total of 122 were HIV positive (61.00%), and 49 were HIV negative (24.50%). High risk HPV was detected in 132 out of 197 patients (67.01%). The final cytology diagnoses were as follows: 114 negative (57.00%), 28 ASC-US (14.00%), 56 LSIL (28.00%), 1 ASC-H (0.50%), and 1 HSIL (0.50%). Cytology diagnostic agreement was 95% with weighted kappa value of 0.899 (95%CI=0.862-0.931). Conclusion The interobserver reproducibility of ThinPrep anal cytology was almost perfect in the setting of MSM population. Acknowledgments National Research University Funds, Japan Society for the Promotion of Science Grants, Faculty of Medicine and Research Institute for Health Science-Chiang Mai University