INCLUSION CRITERIA:  All patients with ulcerative colitis (≥ 16 years) undergoing planned endoscopic assessment as part of standard of care between 01.07.2020 and 30.06.2021. Evidence of a personally signed and dated informed consent document (ICF) indicating that the subject has been informed of all aspects of the study.  EXCLUSION CRITERIA:  Subjects with a diagnosis of indeterminate colitis, ischemic colitis, radiation colitis, diverticular disease associated with colitis, microscopic colitis or Crohn's disease.  Subjects with clinical findings suggestive of CD (e.g. fistulae, granulomas on biopsy) are also excluded. Similar data collection within 8 weeks prior to endoscopic assessment