As the LA criteria were being developed and validated it became clear that the lack of standardized criteria for the endoscopic diagnosis of reflux esophagitis and Barrett’s esophagus were mirrored by lack of standardized criteria for the histologic diagnosis and evaluation of reflux esophagitis.

An independent international group of expert GI pathologists from Europe, Japan and North America was convened at a workshop in 2004 to determine whether the standardization of histologic markers of GERD could be improved. This led, in 2005, to agreement on the histologic markers to be used and the scoring methods to be assessed as the basis for a small-scale interobserver variability check on histologic slides using the agreed criteria with a standardized case report form design and a definition document including the draft histologic criteria for the first study. The consensus document was followed by a report of the initial validation study, published in 2011 as the EsoHisto Project. These two papers have been widely cited in the subsequent literature related to the histological diagnosis of GERD.