24 Hour Oesophageal ph/Impedance Study

What is 24hr pH Impedance Test?

Most people will experience reflux at various points in their lives. There are cases where patients experience severe symptoms such as persistent heartburn, chest pain and regurgitation, but there may be no obvious evidence of reflux on a gastroscopy.

The reflux study involves a reflux and motility (movement) study of your oesophagus (the swallowing tube that transports food from your mouth to your stomach). It is a diagnostic test to determine if you have Gastro-Esophageal Reflux Disease (GERD) or to identify the cause of various gastrointestinal symptoms present.


A small sterilised tube with multiple sensors will be gently inserted down the nose into the oesophagus. This tube contains special tiny sensors and will accurately measure the acidity and impedance of the oesophagus in real-time.

WHEN Should I Get The Procedure

This study is done in cases where patients have persisting symptoms, but there is no clear evidence of reflux induced damage to the oesophagus.

The purpose of this study is to check if you have any reflux and to see if there is a link between your symptoms and reflux. It will also measure the amount of acid that flows from the stomach and into the oesophagus during a 24-hour period.

PREPARING For The Procedure

You may be asked not to take acid suppressing medications for about a week before the test. 

Please check with your doctor regarding any medications you are taking so it will not affect and influence the test results.

BEFORE The Procedure

Fasting with no eating and drinking for 6 hours before your appointment time.

DURING The Procedure

The study involves 2 parts:

Firstly, a small thin tube that measures pressures, will be placed through your nose into your oesophagus. You will then be made to swallow a few sips of water while pressure and distance recordings are taken. The tube will then be removed.

Secondly, a thin wire with sensors to measure both reflux and acidity is passed down the same pathway into the oesophagus based on the pressure measurements taken. Afterwards, it is secured with a bit of tape to your nostril and attached to a small handphone-sized device. This wire is left in place for 24hrs to record reflux. You will return the next day to have the device removed.

Once the wire and recorder are inserted, you are advised to carry out your daily routine as per normal, with NO dietary restrictions. The only restrictions are no swimming is allowed, as the data recorder cannot be wetted; and not to go near an MRI machine.

AFTER The Procedure

You will need to return the next day to have the recorder removed, and the data downloaded and analysed. The report will be sent to your specialist within the next week, where he will discuss with you the test result and advise on the next course of action suitable for you to help you overcome your esophageal symptoms.

SAFETY Of The Procedure

There is minimal risk with the procedure, and the process is the same as inserting a small thin feeding tube. It will not interfere with eating, drinking or swallowing in any way.

QUALITY Of The Procedure

The test is performed at our gutCARE clinic by our neuro-gastro motility specialist. 

The study is interpreted as per the international reflux consensus.