The Promising Role of Intestinal Organoids in the Diagnostic Work-Up of Cystic Fibrosis Screen Positive Inconclusive Diagnosis/CFTR-Related Metabolic Syndrome (CFSPID/CRMS).

Cystic Fibrosis Screen Positive Inconclusive Diagnosis/CFTR-related Metabolic Syndrome (CFSPID/CRMS) presents a significant clinical challenge due to its variable diagnostic outcomes and uncertain disease progression. Current diagnostic strategies, including sweat chloride testing and genetic analysis fall short in delivering clear guidance for clinical decision-making and risk assessment. Here, we comment on the potential of CFTR functional tests in patient-derived intestinal organoids (PDIOs) to enhance early risk stratification in CFSPID/CRMS cases. Using four hypothetical cases based on real-world data, we illustrate diverse clinical trajectories: diagnosis of cystic fibrosis (CF), reclassification as a CFTR-related disorder (CFTR-RD), non-CF designation, and persistent diagnostic uncertainty. Organoid-based assays-such as forskolin-induced swelling (FIS), steady-state lumen area (SLA) analysis, and rectal organoid morphology analysis (ROMA)-offer functional insights into CFTR activity and drug responsiveness. Compared to existing CFTR functional tests, such as Intestinal Current Measurement (ICM) and Nasal Potential Difference (NPD), these assays are more accessible, highly reproducible, and when needed support personalized medicine approaches. PDIO-based assays could help identify infants at high risk of disease progression, facilitating earlier interventions while minimizing unnecessary follow-ups for those unlikely to develop CF-related symptoms. Although not yet widely implemented, these assays hold promise for refining CFSPID diagnostics and management. Future research should focus on establishing standardized protocols allowing validation of clinical utility.