A pH study is a test to measure the amount of acid present in the oesophagus.  It is usually measured over a period of time, such as 24-48 hours.  It is measured either by using a thin probe that passes through the nose into the oesophagus (food pipe) and stays there for the duration of the test, or nowadays, also by a small wireless capsule (Bravo capsule) that can be placed inside the oesophagus with a telescope and transmits data wirelessly to a pager device.

A pH study may be combined with manometry, or measurement of the muscle strength of the oesophagus.  Pressure generated in the oesophagus and at each end where valves are positioned, can be recorded.  This may identify weakness of the oesophagus, hyperactivity or underactivity of the oesophagus and also help to identify where a pH probe should be placed.

pH and manometry testing is performed in the office, then continued for at least 24hrs later at home.  You can eat, drink and continue normal daily activities whilst the probe is in place, and in fact you are encouraged to do so!  This gives the best indication of what your 'normal' day is like.

High acid levels as measured by a pH study may need medication treatment to reduce stomach acid, or its escape into the oesophagus or throat.  Occasionally surgery is required to control severe acid reflux or treat a hiatal hernia.