What is an Esophageal pH–Impedance Study?
An oesophageal pH–impedance study is a diagnostic test that measures both acid and non-acid reflux in the oesophagus. Unlike standard pH monitoring, this test detects episodes of reflux regardless of acidity, making it helpful for conditions where symptoms persist despite treatment with acid-suppressing medicines. Small sensors measure changes in pH and movement of fluid or gas, providing detailed information on the frequency, duration, and type of reflux.
When is an Esophageal pH–Impedance Study Recommended?
A clinician may recommend the test in the following situations:
- Persistent reflux symptoms despite medication
- Suspected non-acid reflux
- Evaluation of chronic cough, hoarseness, or asthma linked to reflux
- Prior to anti-reflux surgery to assess severity
- To confirm gastro-oesophageal reflux disease (GORD) in unclear cases
How is an Esophageal pH–Impedance Study Performed?
The procedure involves passing a thin catheter through the nose into the oesophagus. The tube stays in place for 24 hours and is connected to a small recorder worn on a belt or strap. Patients are asked to continue daily activities, eat normally, and press buttons on the recorder when symptoms occur. After 24 hours, the catheter is removed, and the data are analysed by a specialist.
What to Expect after the Test
Most people can resume normal activities immediately after catheter removal. Mild throat irritation, congestion, or sneezing may occur for a short time. There is no sedation, so driving and working are usually safe straight away.
What are the Risks of an Esophageal pH–Impedance Study?
The test is generally safe, but possible risks include:
- Nasal or throat discomfort
- Minor nosebleeds
- Gagging or coughing
What are the Benefits of an Esophageal pH–Impedance Study?
Clinical benefits include:
- Accurate diagnosis of acid and non-acid reflux
- Identification of symptom triggers
- Support for treatment or surgical decisions
- Improved management of chronic reflux symptoms