The pH meter device is used to precisely measure acid levels within the stomach and esophagus. These measurements play a critical role in the diagnosis and evaluation process of reflux disease based on symptoms. While reflux can be diagnosed using endoscopic methods, stomach acids are elements that cannot be directly seen with the naked eye. Acid reflux can occur even in cases where structural damage such as ulcers, erosions, or significant inflammation has not yet developed in the esophagus. The pH meter device allows for the recording of acid reflux episodes that cannot be detected by endoscopic examination, thereby enabling a more accurate and comprehensive diagnosis of the disease.