Fecal, Blood, and Urinary Biomarkers in Inflammatory Bowel Diseases

The incidence and prevalence of inflammatory bowel diseases (IBD), including ulcerative colitis and Crohn’s disease, are rapidly increasing. Currently, colonoscopy is the gold standard for diagnosing and monitoring the course of IBD. However, the recently implemented “treat-to-target” strategy, which involves meticulously pursuing multiple therapeutic objectives, has opened avenues for non-invasive diagnostic and monitoring tools. These tools aim to assess disease activity and predict the likelihood of recurrence. Research studies into serum and fecal biomarkers in IBD have been ongoing for several years. Among the most relevant biomarkers, fecal calprotectin and C-reactive protein have shown the best accuracy, with good-to-optimal correlation with endoscopic, histologic, or transmural activity. Numerous studies have explored the potential advantages of using multi-target tools that combine serum and fecal biomarkers with clinical activity indexes to enhance diagnostic and monitoring effectiveness. Encouraging findings have emerged for fecal lactoferrin, autoantibodies, micro-RNA, gene expression, and many other serological and fecal markers. However, limited evidence has hindered their widespread adoption in routine clinical practice. This review aimed to summarize the available data on the utilization of biomarkers in IBD.