It is not clear whether we should test for reflux in patients with refractory heartburn or extra-esophageal reflux (EER) symptoms, such as cough, hoarseness, or asthma. Guidelines recommend testing patients by pH monitoring when they are on or off acid-suppressive therapies based on pre-test probability of reflux, determined by expert consensus. However, it is not clear what constitutes a low or high pre-test probability of reflux in these patients. We aimed to develop a model that clinicians can use at bedside to estimate pre-test probability of abnormal reflux.