To diagnose GERD , in 24 hour ambulatory pH testing the percentage of the day that the pH was less than 4 is:: (A) > 20%, (B) > 1%, (C) > 5 %, (D) > 1 %
Answer is C. The percentage of the day that the pH was less than 4 with values exceeding 5% indicative of GERD.Intraluminal impedance monitoring can be added to pH monitoring to detect reflux events irrespective of whether or not they are acidic. Ref : Harrison, E-18, P- 2428