Bravo Catheter-Free pH Monitoring: Normal Values, Concordance, Optimal Diagnostic Thresholds, and Accuracy  Shahin Ayazi, John C. Lipham, Giuseppe Portale, Christian G. Peyre, Christopher G. Streets, Jessica M. Leers, Steven R. DeMeester, Farzaneh Banki, Linda S. Chan, Jeffrey A. Hagen, Tom R. DeMeester  Clinical Gastroenterology and Hepatology  Volume 7, Issue 1, Pages 60-67 (January 2009) DOI: 10.1016/j.cgh.2008.08.020 Copyright © 2009 AGA Institute Terms and Conditions

Figure 1 Bland–Altman plots comparing (A) total time the pH was less than 4 and (B) the composite pH score as measured by the Bravo pH capsule in 50 asymptomatic subjects on 2 consecutive days. The mean difference between day 1 and day 2 is plotted against (A) the total time the pH was less than 4 and (B) the composite pH score for each subject. The dashed lines represent the 95% limits of agreement (±2 standard deviations). These limits of agreement define an interval within which 95% of differences between measurements are expected to lie. All but one subject fell within the limits of agreement. Clinical Gastroenterology and Hepatology 2009 7, 60-67DOI: (10.1016/j.cgh.2008.08.020) Copyright © 2009 AGA Institute Terms and Conditions

Figure 2 Composite pH score for the first and second 24-hour recording periods using the Bravo pH capsule in 25 normal subjects (solid lines) and 25 symptomatic patients (dotted lines). The horizontal line represents the optimal threshold for the composite pH score (14) determined by logistic regression. Clinical Gastroenterology and Hepatology 2009 7, 60-67DOI: (10.1016/j.cgh.2008.08.020) Copyright © 2009 AGA Institute Terms and Conditions