Impedance testing provides additional clinical information compared with pH testing alone in the diagnosis of patients with reflux symptoms, especially when atypical symptoms are present or the response to PPI has been inadequate. It may be helpful to the clinician to categorize patients with symptoms truly attributable to reflux versus another cause of symptoms (eg, functional heartburn), although outcomes studies have not been performed to determine whether this truly leads to a change in management. MII-EM testing can diagnose whether a functional defect truly exists in patients with dysphagia and other symptoms such as noncardiac chest pain, especially in patients with manometric diagnoses of ineffective esophageal motility and diffuse esophageal spasm. Improved outcomes based on MII-EM testing may be difficult to demonstrate because of the lack of effective therapy for these patients. The results of future studies should clarify when impedance testing should be performed and what change in management can be expected based on the results, as well as the relative cost benefit of such testing. © 2012 American Society for Gastrointestinal Endoscopy.
Wang, A., Pleskow, D. K., Banerjee, S., Barth, B. A., Bhat, Y. M., Desilets, D. J., … Rodriguez, S. A. (2012). Esophageal function testing. Gastrointestinal Endoscopy, 76(2), 231–243. https://doi.org/10.1016/j.gie.2012.02.022