It can measure resting LOS pressure and abnormality in peristalsis. The method by which GOR is best diagnosed. A reference electrode is attached to the skin and recordings are made continuously for an extended period. In some studies, pH electrode is positioned fluoroscopically to lie in distal third of oesophagus. The higher in the oesophagus the tip of probe placed, the higher the risk of a false negative results.
Test is easy to perform, but interpretation is difficult.
Because the usual infant formula obscures the detection of GOR secondary to gastric buffering effect, clear liquids and juices are offered during the study. All positional changes are noted on a bedside logbook. Recording also should be performed during periods of sleep. Computer assisted interpretation is available in analysing information obtained from the study. Until recently, most pH studies were performed in the hospital, were position, feeding type and frequency could be controlled.