False Positives in Esophageal pH Monitoring: The Pitfalls of Single-Value Interpretation

Background/Objectives: Esophageal pH monitoring is a key diagnostic modality in the evaluation of gastroesophageal reflux disease (GERD) and employs either a traditional transnasal catheter or wireless probe. In clinical practice, findings from these studies are often represented by a single metric, such as acid exposure time (AET), designed to quantitatively summarize reflux burden. However, these composite scores are susceptible to error derived from sensor position, patient diet and posture, transient pH fluctuations, anatomical variations, and esophageal motility. This study sought to identify false-positive mechanisms in esophageal pH testing. Methods: We retrospectively identified institutional logs of false-positive pH findings from a single medical center from January 2019 to January 2025, and in conjunction with expert opinion, we classified false-positive patterns based on the original clinical interpretation. Results: The most common mechanism was technical error originating from factors that directly impact sensor integrity, such as a dislodged capsule or withdrawal of the transnasal catheter. Additional confounders comprised patient-specific variables, including esophageal stasis or behavioral disorders like belching or rumination syndrome. Conclusions: Ultimately, false-positive GERD findings are uncommon but can occur when AET is derived from misleading data. We also sought to develop a diagnostic framework that incorporates clinical context, adjunctive testing, and sensor verification protocols in order to mitigate confounders inherent to ambulatory pH monitoring. This study represents one of the first evaluations of false-positive patterns in esophageal pH testing, offering insight that may ultimately enhance precision and clinical decision-making in the diagnosis of GERD.