The Indian Academy of Cytologists Guidelines for Reporting Serous Effusion (IACGRSE): An Interobserver Agreement Analysis

CONTEXT: The Indian Academy of Cytologists published Guidelines and categories for Reporting Serous Effusions (IACGRSE) in 2020 to improve consistency and reproducibility of fluid cytology reporting and to guide patient management. AIMS: To evaluate category-wise agreement while using IACGRSE 2020 categories. To analyze interobserver agreement among participants with different level of training and years of experience. SETTINGS AND DESIGN: A retrospective interobserver variability study. METHODS AND MATERIAL: Study was done with four participants: an expert cytopathologist and three cytopathology fellows with varying experience. Fluid smears from 60 cases with clinical and/or radiological evidence of malignancy were categorized into one of the five IACGRSE 2020 categories. The interpretations of expert cytopathologist were taken as standard. STATISTICAL ANALYSIS USED: Interobserver agreement was analyzed using Kappa statistics. RESULTS: Previous cases without definitive category got classified into “Atypical cells NOS” (3.33%) and “Atypical cells, Suspicious of Malignancy” (15%). Agreement analysis for IACGRSE 2020 categories showed better concordance for inadequate (I), malignant (V), and benign (II) categories. The range of Kappa for interobserver agreement of fellows was fair to substantial (range 0.1692–0.7249). The participant with substantial diagnostic agreement with expert (κ = 0.729, 88.3%) had the most experience. Causes of major discordance were pertaining to paucity and distribution of cells, and to misinterpretation of reactive mesothelial cells. CONCLUSIONS: IACGRSE 2020 categories and participants’ experience were important determinants in classifying the effusion fluid cytology smears and interobserver agreement; emphasizing the need to use IACGRSE2020, and sufficient time and training required for accurate diagnosis of fluid specimens.