Bethesda Interobserver Reproducibility Study-2 (BIRST-2): Bethesda System 2014

Similar to the BIRST-1 study conducted in 2001, the most important factor for diagnostic agreement by cytotechnologists, pathologists, and trainees was the a priori difficulty of an image rather than participant training, certification, or experience. Participants showed better general diagnostic agreement with the expert panel interpretations of the material in BIRST-2 than in BIRST-1. Agreement was highest for Bethesda categories of NILM, LSIL, HSIL, and SCC. Concordance for even the borderline ASC-US and ASC-H categories exhibited remarkable improvement in the BIRST-2.