Cytology-histology correlation of gynecologic and non-gynecologic samples at a tertiary health care center: A two-year study

Background: Cytology-histology correlation is a method of detection of an error in the diagnostic field. The root cause analysis is done for the discordant cases for quality improvement of the laboratory reports. Aims: To find out the root cause in discordant cytology-histology case pairs. Methods: This is a Retrospective cross-sectional descriptive study. The study was done from January 2016 to December 2017. All FNAC and Pap test cases which had corresponding biopsy slides and reports are included in the study. The discordant cases were classified as sampling error, interpretation error, cytology error, and histopathology error. Descriptive statistical analysis was used for the analysis of results. Results: Of total 639 case pairs, gynecologic case pairs were 447, and nongynecologic case pairs were 192. Among the gynecologic cases, the concordance between cytology and histopathology diagnosis were 425 (95%) and discordance 22 (5%) of which discrepancy in cytology was 11, histopathology was seven, and both cytology and histopathology error was four. The interpretation error was 14, and the sampling error was nine. Among non-gynecologic cases, the concordance between cytology and histopathology diagnosis were 167 (86%) and discordance 25 (14%) of which discrepancy in cytology was 17, histopathology was seven, and both cytology and histopathology error was one. The interpretation error was 16, and the sampling error was ten. The discordance versus concordance ratio was 1:19.3, 1:6.68 and 1:12.5 for gynecology, non-gynecology, and total case pairs respectively. Conclusions: The percentage of error in gynecologic cases was within the range of published data. However, those of non-gynecology cases were slightly higher. Regular professional training and improvement of sampling techniques especially the guided FNAC can reduce the errors.