Inflammatory bowel disease (IBD), primarily ulcerative colitis (UC) and Crohn's disease (CD), is a chronic disease entity affecting individuals of all ages, and which may severely impact the lives of the patients and their families as well as society. Individuals with IBD may have to live with relapsing symptoms, such as diarrhea, abdominal pain, and fatigue. Further, a substantial proportion of patients develop serious complications such as bowel obstruction and fistula, and some develop complicating liver disease and eventually colorectal cancer. The consequences are that many patients suffer hospitalizations, recurring sick-leave, life-long medication, and surgical interventions. As IBD has become increasingly common in Western populations there is a clear need to improve the outcome from IBD. IBD is a heterogeneous disease entity with substantial differences between patients and personalized medicine may help provide strategies for better treatment . Currently, one of the main unmet needs is the glaring lack of robust biomarkers for individual disease characterization. This lack leads to delayed diagnosis, worse outcomes, increased mortality and an amplified disease burden. Furthermore, diagnosis of IBD is difficult and early diagnosis is crucial as it helps avoid the development of irreversible organ damage. Therefore, there is an emerging focus on the development of simple, non-invasive, and cheap biomarkers to support clinical decision-making in IBD. This Nordic, prospective, clinical study has the aim of identifying markers that are associated with the diagnosis of IBD and prediction of clinical outcomes with various disease manifestations. Importantly, this study will evaluate the markers in a relevant clinical setting, i.e. among patients referred to the hospital for suspicion on IBD using the ECCO Criteria. Specifically the aims of the study are to: * Improve the accuracy to diagnose IBD * Improve the accuracy to define the prognosis of IBD The study is approved by the local Ethics Committee (S-20200051) and the local Data Agency (20/54594).