Impedance testing in reflux evaluation helps detect what in addition to acid reflux events?

• A. Esophageal motility assessment
• B. Nonacid reflux events
• C. Gastric emptying
• D. Hiatal hernia detection

Answer: (B)

Impedance testing expands reflux assessment by detecting reflux events no matter the acidity. It uses multiple impedance sensors along the esophagus to sense changes in electrical resistance as a bolus moves. When a reflux episode occurs, the bolus—whether liquid or gas—changes the impedance pattern and can be identified even if the pH isn’t lowered. That means nonacid reflux events, which pH monitoring alone would miss, are detected alongside acid reflux. This is especially helpful for patients on acid-suppressive therapy, where symptoms may be driven by nonacid reflux. While impedance testing can also help track how far reflux reaches up the esophagus and distinguish swallows from reflux, its key value here is revealing nonacid reflux in addition to acid reflux.