https://www.selleckchem.com/products/GDC-0449.html Background/Aims Mean nocturnal baseline impedance (MNBI) during multichannel intraluminal impedance pH-monitoring (MII-pH) reflects the status of esophageal mucosal integrity. MNBI is suggested as an adjunctive method to distinguish patients with true gastroesophageal reflux disease (GERD) from functional heartburn (FH) and might predict outcomes for anti-reflux treatment. However, current methodology for calculation of MNBI is time-consuming and subject to operator-dependent selection bias. We aim to simplify and provide a more objective method to calculate MNBI. Methods We retrospectively analyzed 100 MII-pH tracings from 20 patients with erosive reflux disease, 20 with non-erosive reflux disease (NERD), 20 with reflux hypersensitivity, 20 with functional heartburn (FH), and 20 healthy asymptomatic volunteers. We compared the current "conventional" MNBI analysis with our "simple" MNBI analysis measured by selecting the whole supine period using the impedance average calculation function in the MII-pH software. Results Absolute values were very similar and there was a strong correlation between conventional and simple MNBI values in the most distal channel in all groups (r ≥ 0.8, P less then 0.001) including patients with increased supine acid reflux. Distal esophageal simple MNBI negatively correlated with acid exposure time (r = -0.695, P less then 0.001). Patients with erosive reflux disease and NERD had lower simple MNBI values in the most distal channel compared to other groups (P less then 0.001). With a cutoff value of 1785 ohms, simple MNBI can discriminate patients with GERD from those with reflux hypersensitivity and FH (sensitivity 80.0% and specificity 89.7%). Conclusion Simple MNBI analysis provides very similar values and has an excellent correlation with conventional MNBI analysis.Background/Aims High-resolution manometry (HRM) has broadened the awareness of minor esophageal peristaltic disorders. Ho