Continuous oesophageal pH recording and acid-clearing test. A study of reproducibility.

Ten investigations of acid reflux by means of 12-hour continuous pH monitoring at the distal end of the oesophagus, and 10 acid-clearing tests were performed within 6 weeks on the same volunteer with the purpose of examining the reproducibility of the results of these tests. Intragastric pH was studied over 12 hours and proved to be under 3 during the whole period of investigation. For the acid reflux test the coefficient of variation was 0.61-0.94, depending on the criteria for reflux. For the acid-clearing test the coefficient of variation was 0.22. For both tests the results of the separate investigations varied within normal ranges.