KASID Guidelines for Diagnosis and Monitoring of Inflammatory Bowel Disease: 2026

Inflammatory bowel disease (IBD) is characterized by heterogeneous disease presentations and clinical courses. Accurate diagnosis and appropriate disease monitoring play an important role in improving long-term outcomes by preventing misdiagnosis and unnecessary treatment; enabling early detection of disease progression, treatment failure, and disease-related complications; and facilitating timely adjustment of treatment strategies. The Korean Association for the Study of Intestinal Diseases (KASID) developed guidelines for the diagnosis and monitoring of IBD in adults, reflecting the Korean clinical setting, to support clinical decision-making and improve the quality of patient care. To develop these guidelines, existing international clinical practice guidelines and expert consensus statements were comprehensively reviewed, along with updated evidence relevant to each clinical topic. Final recommendations were established through expert consensus using a modified Delphi process. These guidelines address major clinical areas in the diagnosis and monitoring of IBD, including initial diagnosis and baseline assessment, assessment of disease extent and activity, disease monitoring in ulcerative colitis and Crohn's disease, nutritional assessment, and colorectal cancer surveillance. These guidelines are intended to support individualized clinical judgment and should be applied flexibly, taking into account not only individual patient characteristics and clinical circumstances but also available resources, access to diagnostic and monitoring modalities, regulatory requirements, and reimbursement policies.