Calprotectin is well known in gastroenterology as a non-invasive biomarker for active disease in patients with Inflammatory Bowel Disease (IBD). Its use, however, is not limited to differential diagnosis and follow-up of IBD patients; it is a general biomarker that has gained a lot of increased focus within research and drug development in the past decades, challenging traditional inflammatory biomarkers such as C-Reactive Protein (CRP).