['The Bravo capsule allows monitoring of esophageal acid exposure over a two-day period. Experience has shown that 24-32% of patients will have abnormal esophageal acid exposure detected on only one of the 2 days monitored. This variation has been explained by the effect of endoscopy and sedation. The aim of this study was to assess the day-to-day discrepancy following transnasal placement of the Bravo capsule without endoscopy or sedation and to determine factors related to this variability.', 'Bravo pH monitoring was performed by transnasal placement of the capsule in 310 patients. Patients were divided into groups based on the composite pH score: both days normal, both days abnormal and only one of the 2 days abnormal. Lower esophageal sphincter (LES) characteristics were compared between groups.', 'Of the 310 patients evaluated, 60 (19%) showed a discrepancy between the 2 days. A total of 127 patients had a normal pH score on both days and 123 had an abnormal pH score on both days. Of the 60 patients with a discrepancy, 27 were abnormal the first day and 33 (55%) were abnormal the second day. Patients with abnormal esophageal acid exposure on both days had higher degrees of esophageal acid exposure and were more likely to have a defective LES compared to those with an abnormal score on only one day (35 vs. 83%, p=0.027).'] Is day-to-day discrepancy in Bravo pH monitoring related to the degree of deterioration of the lower esophageal sphincter and severity of reflux disease?