Acid and reflux testing are used primarily to diagnose acid reflux into the esophagus. Other less commonly used tests are gastric fluid analysis and tests to assess bile reflux. Complications are very rare in these processes. Patients must stay sober since midnight on examination day, but they are allowed to eat as usual after the monitoring device is placed. Ambulatory pH monitoring An ambulatory 24-hour esophageal pH monitoring with or without intraluminal impedance test is currently the most widely used test method for the quantification of gastroesophageal reflux. The main indications are: documentation of excessively azidem or nichtazidem reflux correlation of symptoms with reflux episodes identifying candidates for antireflux surgery evaluation of the effectiveness of medical or surgical treatment measures The tests use a transnasal continuous reflux monitoring via a catheter or a wireless pH monitoring device which is endoscopically attached to the distal esophagus. Catheter-based monitoring A thin catheter containing a pH probe is positioned 5 cm above the lower esophageal sphincter. The patient documented over 24 h symptoms, meals and sleep. The oesophageal acid contact is defined as the proportion (%) of the whole monitoring time, during which the pH is <4.0. A value> 4.3% is considered abnormal when the patient has taken a proton pump inhibitor, and a value> 1.3% is considered abnormal when the patient for the duration of the test is under the effect of a proton pump inhibitor. Additional sensors along the more proximal regions of the pH probe allow identification of proximal reflux episodes. The newer pH monitoring devices allow also usually intraluminal (pH> 7) can identify multi-channel impedance tests that weakly acidic reflux (pH 4.0 to 7) and non-acid reflux, which is not possible with the conventional pH monitoring devices was. The correlation between the reported patient symptoms and reflux events can (symptom association probability, SAP) using the symptom index (SI) or symptom associated probability be assessed. A significant SI value or SAP value indicates that the correlation between symptoms and reflux events is not accidental. Excessive reflux and significant symptom-reflux correlation are positive predictors of a positive outcome in Antirefluxchirurgie.Drahtlose monitoring The ambulatory esophageal pH monitoring can also take place by means of wireless pH sensor capsule which is attached to the distal esophagus. The device is endoscopically placed 5 cm above the lower esophageal sphincter and continuously measures the oesophageal acid exposure (defined as pH <4.0) for 48 h. Similar to the probe-based test, the patients keep symptoms, meals and sleeping fixed for the duration of the test, resulting in excessive acid exposure and symptom-reflux correlation (SI or SAP) can be identified. However, since the capsule is a pure pH sensor detects only more acidic reflux. The capsule dissolves generally within a week from its attachment and is excreted in the feces spontaneously. Since the capsule wirelessly transmits its data after attachment, there is no need to retrieve it. Gastric juice analysis Gastric juice analysis is nowadays rarely durgeführt. Will it still causes samples are obtained from the stomach contents through a stomach tube and used for the determination of basal and stimulated gastric acid secretion. This information is useful in a patient who has suffered an ulcer recurrence after surgical vagotomy to treat his ulcer disease. In these cases, a positive reaction indicates a stimulation acid (apparent meal) on an incomplete vagotomy. The test is also used to clarify patients with elevated Serumgastrinspiegeln. Hyperacidity in the presence of elevated gastrin usually refers to Zollinger-Ellison syndrome. A hypochlorhydria in the presence of elevated gastrin indicates a reduction in the production of acid, such as occurs by potent antisecretory drugs in pernicious anemia, atrophic gastritis, ankylosing a Ménétrier and according to the inhibition of gastric acid secretion. To perform a gastric juice analysis, a feeding tube is introduced aspirated gastric contents and initially discarded. The gastric juice is then collected for an hour and divided into four 15-minute samples. These samples represent the basal acid secretion.