Esophageal pH monitoring and impedance measurement: a comparison of two diagnostic tests for gastroesophageal reflux.

Background: pH monitoring is the standard diagnostic tool for gastroesophageal reflux in infants. However, this method does not document the reflux of all kinds of fluid from the stomach into the esophagus, but only documents acid material. The parameters that define reflux episodes by pH monitoring have been derived empirically from observations of many infants considered healthy and ill.