Recent Trend of Laboratory Tests in Common Gastrointestinal Tract Disorders

The gastrointestinal (GI) tract is a complex organ system affected by multiple disorders with diverse etiologies ranging from infections to immune dysfunction disorders and cancers. Various GI disorders, such as Helicobacter pylori infection, inflammatory bowel disease (IBD), celiac disease, irritable bowel syndrome (IBS), and colon cancer, are common and cause significant morbidity, mortality, and healthcare costs. These disorders present with overlapping signs and symptoms, warranting the need for accurate laboratory diagnostic tests for appropriate treatment implementation and treatment monitoring. The gold standard confirmatory diagnostic test for most GI disorders is endoscopy and biopsy for histological analysis. Biomarkers in blood and stool are also routinely used either as first-line screening tests or for treatment monitoring in many GI disorders. This review summarizes common GI disorders along with related currently used clinical laboratory tests in screening, diagnosis, and monitoring of these diseases, outlining the methodology, utilization, advantages, and limitations of these tests. We also highlight the effectiveness of each test as well as the professional recommendations and clinical guidelines for their use where available. Finally, we shed some light on potential future tests and biomarkers that aid in diagnosing GI disorders and how these biomarkers can be used in conjunction to complement the current tests. Some of the potential future biomarkers discussed include the differential expression of gut microbiota and their respective metabolites, as well as cytokines, as potential tests that can be used to diagnose diseases, distinguish between disease subtypes, predict disease severity and occurrence, and optimize treatment decisions. Comprehending the effectiveness of various methodologies for laboratory diagnosis of GI disorders is crucial for health care personnel, including clinical laboratory professionals and clinicians, regarding testing options, test utilization, and interpretations of results. Insights into future tests in GI diseases in the context of microbiomes, metabolites, and immune mediators based on advanced technology are also important in their appropriate clinical utilization.