We provide comprehensive & personalised OESOPHAGEAL IMPEDANCE AND PH STUDIES.


Gastro-oesophageal reflux disease (GORD) is very common. It occurs when the acidic contents of the stomach flow into the oesophagus (swallowing tube). This can cause a range of symptoms, including:

  • Burning chest pain
  • Indigestion
  • Upper abdominal pain
  • Chronic cough
  • Chronic sore throat
  • Recurrent chest infections
  • Bad breath
  • Poor dentition

Typically these symptoms can be treated with antacid remedies and acid-blocking drugs (e.g. omeprazole, pantoprazole, lansoprazole or ranitidine), although these are not always effective. Often a Gastroscopy is needed to confirm the diagnosis and exclude complications.

When drug treatment is not effective, not tolerated, or anti-reflux surgery is to be considered, then confirming the diagnosis with accurate physiological testing is essential.

Ambulatory 24-hour oesophageal impedance and pH studies are one of the best ways to confirm the presence of reflux and its severity. A thin, flexible catheter is passed through the nose and down the oesophagus. It is attached to a small data recorder and measures fluid (impedance) and acidity (pH) in the oesophagus. The catheter remains in place for 24 hours. The patient can also record when they have symptoms which can be correlated with the recording. The data is then downloaded into a computer and analysed by our Gastroenterologists.

Our staff are experienced in the placement and interpretation of ambulatory 24-hour oesophageal impedance and pH studies and we are a Southern Cross Affiliated Provider for oesophageal pH studies.

(For medical professionals)

How to refer for pH/manometry 
Please ensure to include medication status on referral for pH studies.

Frequently asked questions

What is a 24-hour pH study?

A 24-hour pH study is often done in conjunction with oesophageal manometry to monitor the levels and changes in acid content in the oesophagus over a 24-hour period, while the patient conducts his or her normal daily activities. It is used to diagnose gastro-oesophageal reflux disease (GERD – digestive acid passing from the stomach up into the oesophagus), to determine the effectiveness of medications that are given to prevent acid reflux and to determine if episodes of acidic reflux are causing chest pain.

How does it work?

A smaller tube than that used for oesophageal manometry is passed through the nose into the oesophagus in the same manner as for manometry. This tube is connected to a small recording device that is worn on a belt for the following 24 hours. Food diaries are completed by the patient over the 24-hour period following tube placement to record all food and fluid taken. Diaries should also include information about sleep patterns and symptoms. Symptoms are recorded via the recording device to allow them to be related to episodes of reflux. The tube is removed the next day.

Who would have a 24-hour pH study?

  • Heartburn or reflux
  • Chest pain
  • Difficulty swallowing

Contact us today

Appointments are available

(03) 662 9458

40 Stewart St. Christchurch 8011, NZ

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24-hour PH studies