Biomarkers in Irritable Bowel Syndrome: Bridging Gut-Brain Mechanisms to Precision Care

Irritable bowel syndrome is a common disorder of gut-brain interaction characterized by chronic abdominal pain and altered bowel habits in the absence of structural pathology. Its pathophysiology reflects a complex interplay between the central nervous system, enteric nervous system, microbiota, immune signaling, epithelial barrier dysfunction etc. Despite advances in the understanding of the mechanisms causing IBS, the diagnosis of IBS remains primarily symptom-based, necessitating the use of objective tools to improve diagnostic precision and personalized management. This review synthesizes highlights existing literature on IBS biomarkers, including inflammatory markers (cytokines, C-reactive protein), microbial signatures (gut microbiota composition, anti-CdtB and anti-vinculin antibodies), metabolic indicators (bile acids, short-chain fatty acids), and markers of intestinal permeability (zonulin) to assess their applications in the diagnosis and management of IBS. We also examined emerging multi-omics technologies that identify the complex patterns linking the gut, the brain and the microbiota. Early research focusing on single biomarkers demonstrated limited diagnostic utility due to the heterogeneous and multifactorial nature of IBS. Recent advances support the development of composite, mechanism-based biomarker panels that integrate multiple biological domains, offering improved representation of underlying pathophysiological processes. These developments mark a shift from a single-marker approach toward multidimensional biomarker strategies. This narrative review synthesizes current evidence and proposes a framework for integrating biomarkers into clinical practice. Biomarkers are best utilized following a positive symptom-based diagnosis and exclusion of alarm features, to stratify patients into biologically relevant subtypes and guide targeted therapy. This supports a transition from exclusion-based diagnosis of IBS towards a positive and more precise one.