reflux of barium during radiographic examination is only positive in 25% 75% ofsymptomatic patients and is falsely positive in almost 20% of normal controls [75] The aforementioned diagnostic tests are mostly invasive, costly and usually not readily available for the practicing physicians. The proton-pump inhibitor (PPI) test is an alternative noninvasive test for the diagnosis of GERD at the disposal of every primary care physician. This test comprises a short course of high-dose PPI (usually omeprazole) and is used as a first-line diagnostic strategy [52]. The notion of the test is based on the hypothesis that if a patient reports symptoms consistent with GERD and responds to therapy with PPI, then he/she should have GERD. The strategy of PPI test is not as robust at patients with non- erosive reflux disease as it is in patients with esophagitis