Review article: indeterminate colitis – definition, diagnosis and management

Summary Background The term indeterminate colitis is imprecise and without a generally accepted definition. Nevertheless, it is a term that is commonly used by gastroenterologists, pathologists and surgeons. Aim To offer an opinion supported by published data, about the appropriate use of the term indeterminate colitis by addressing a series of questions. Methods A PubMed database search was performed using the keywords, ‘colitis’ and ‘inflammatory bowel disease’ each combined individually with the following adjectives: ‘indeterminate’, ‘unclassified’, ‘undefined’, ‘undiagnosed’ and ‘non‐specific’. Results There is no generally accepted definition of indeterminate colitis. All current applications of the term rely on exclusionary criteria and there is no confirmatory diagnostic test. Nevertheless, the diagnosis of indeterminate colitis appears to be durable in a subgroup of patients, suggesting that this group represents a unique phenotype. Conclusions Indeterminate colitis has expanded from a strictly defined, postcolectomy pathological diagnosis to become, in addition, a clinical diagnosis without generally accepted criteria. A diagnosis of indeterminate colitis should be qualified with descriptors for the diagnostic criteria applied.