24 hour oesophageal pH-Impedance study

Sometimes the diagnosis of acid reflux can be difficult to confirm or refute. Gastroscopy is the key test but this is often normal even when there are significant reflux symptoms.

If the symptoms are typical and there is a good response to medication (usually Losec or Somac) then there is no problem.

However if there continues to be uncertainties about the diagnosis and the treatment is not working then further testing can be useful.

The most useful test is a 24 hour oesophageal pH-Impedance study (sometimes abbreviated to 'pH test'). This involves directly measuring the acidity (or pH) in the oesophagus over a day. To do this a fine catheter is inserted through the nose (after local anaesthetic is applied to the nose) and passed into the oesophagus. This is done without sedation as full co-operation is needed to swallow the catheter: this usually only takes a few minutes.

Initially there may be some discomfort in the back of the throat but perhaps surprisingly the catheter is tolerated well and normal activities can continue for the rest of the day. The catheter is taped to your nose to fix the position and the recorder is secured with a waist belt. Although most people do not go to work during the day of the study it is possible to continue your normal pattern eating, drinking and sleeping. The catheter is connected to a small recording device rather like a 'walkman'. This records the pH every 6 seconds.

At the end of the study this recording device is connected to a computer and a graph of pH levels over the day is produced. You will be asked to enter directly into the device the times of meals, sleeping and any symptoms. This will help determine if acid reflux is the main problem or perhaps if there is another explanation for your symptoms. The test requires careful interpretation and it is important to have review by a Gastroenterologist after the test to discuss the results and how the test might affect further treatment options. One important decision is whether to perform the test on treatment or off treatment.