Ambulatory oesophageal pH-metry. Position paper of the Working Team on Oesophageal pH-metry by the GISMAD (Gruppo Italiano di Studio sulla Motilità dell'Apparato Digerente).

In the last three decades, oesophageal pH monitoring has progressed from a physiological research tool to a routine outpatient clinical investigation in patients with suspected gastro-oesophageal reflux disease, one of the most common gastrointestinal disorders. Technological progress has considerably simplified both the procedure and the interpretation of data obtained, and there is currently reasonable consensus as to the parameters that best discriminate between physiological and pathological reflux. There remains a need for internationally agreed definitions and standards with regard to indexes to quantitate the extent and the significance of the relationship between occurrence of symptoms and reflux episodes during the examination. It is felt that national or local normal values are to be used to circumvent different eating habits and other socio-cultural differences which may influence gastro-oesophageal reflux. The reproducibility of the test appears, at present, to be at least good enough to allow classification of the patient as a pathological or physiological refluxer, albeit wide day-to-day variations seem to exist as far as concerns the extent of gastro-oesophageal reflux. Clinical applications of the technique have increased with better knowledge of the protean clinical manifestations of gastro-oesophageal reflux disease, and include the evaluation of "typical" gastro-oesophageal reflux disease patients with negative endoscopy or refractory oesophagitis, the "atypical" manifestations of gastro-oesophageal reflux disease and the pre- and post-operative evaluation of patients undergoing antireflux surgery.