NAZA - Nottingham/Astra ZenecA Prospective IBD Cohort Study

Inclusion Criteria: 1\. Provision of signed and dated, written informed consent before any study specific procedures AND 2a. Patients of at least 16 years of age with active Crohn's disease defined as: CRP \> = 5 mg/L OR FCP \> = 250 μg/g OR Visible ulcerations on ileocolonoscopy with a total SES-CD \> = 7, or \> = 4 if disease is confined to the terminal ileum OR visable active disease on cross-sectional imaging. Are switching to a new mechanism of action (MOA) onto anti-TNF therapy or ustekinumab or upadacitinib OR 2b. Patients of at least 16 years (no upper age limit) with active UC defined as: CRP \> = 5 mg/L OR FCP \> = 250 μg/g OR Mayo endoscopy subscore \> = 2. Are switching to a new mechanism of action (MOA) onto either anti-TNFα therapy or vedolizumab OR 2c. Non-IBD participants who are attending for a lower GI colonoscopy at any participating site. On any hospital/ medical/ clinical screening list or any other appropriate list with no pathology found on examination. Exclusion Criteria: 1. Inability to give informed consent 2. Any positive result from previous screening for serum hepatitis B surface antigen, hepatitis C or human immunodeficiency virus (HIV) 3. An ongoing infection requiring treatment 4. Clinical evidence of active COVID infection and/or evidence of active COVID determined by local standard care procedures 5. Participation in a clinical study with pharmacological intervention within 3 months prior to Baseline visit. 6. Current diagnosis of cancer 7. Having received a solid organ or stem cell transplant 8. Having received a transfusion of blood, plasma, or platelets within 120 days prior to enrolment 9. Confirmed pregnancy at time of enrolment 10. For non-IBD participants: A prior history of IBD (CD, UC, microscopic colitis, indeterminate colitis or IBD unspecified) 11. Clinical judgement by the investigator that the patient should not participate in the study 12. Under 16yrs of age