Esophageal Impedance-pH Study
Also known as: 24-hour pH impedance, 24-hour esophageal impedance pH test.
What is esophageal impedance-pH study?
The pH of something refers to its acidity on a scale. An esophageal pH-impedance study is a test performed in the esophagus that helps to diagnose acid and non-acid reflux.
What happens during the procedure?
Guided by X-ray, medical professionals will pass a catheter through the nose and into the esophagus. The catheter has an acid and non-acid-sensitive tips that measure pH levels in the esophagus over a 24-hour period. This information is then used to make a diagnosis and can be used to guide treatment.
Is any special preparation needed?
The patient may need to avoid foods, drinks and certain medications for a period of time before the test.
What are the risk factors?
Sore throat, fever, fatigue or vomiting are potential risks of an esophageal impedance-pH study.Reviewed by: Carrie Firestone Baum, MD
This page was last updated on: September 16, 2025 12:41 PM
Gastroenterology
Specializing in the treatment of gastrointestinal disorders for infants, children and adolescents.
Learn MoreUse the symptom checker tool to check how serious your symptoms are, if a healthcare visit is needed, and what steps you can take to relieve your symptoms at home.