Testing of the Esophagus
An esophagram is a radiographic study of the esophagus in which the patient swallows barium (a contrast agent) and the radiologist visualizes the esophagus and stomach under fluoroscopy. This test can help detect if there is a problem with a stricture (narrowing) in the esophagus or if a hiatal hernia is present. It can also give a rough estimate of the degree of esophageal muscle contractions.
Upper endoscopy is a test that allows direct visualization of the lining of the esophagus, stomach, and upper portion (duodenum) of the small intestine by the use of an endoscope passed through the mouth. Direct visualization of the esophageal lining allows a check for potential damage (esophagitis, ulcers).
Esophageal manometry involves a small diameter tube passed through the nose into the esophagus. The nose and throat of the patient are numbed prior to this procedure. Once the tube is in position, the patient is asked to swallow. Measurements of esophageal function are made by the use of pressure readings of the muscle contractions (motility) of the esophagus. Lower esophageal sphincter muscle pressure can also be taken. This test helps physicians interpret whether there is a problem with motility of the esophagus or the function of the lower esophageal sphincter (LES).
Ambulatory 24-hour pH probe
An ambulatory 24-hour pH probe is a test that consists of a small tube passed through the nose into the esophagus at the level of the LES. A pH sensor at the tip of the tube allows measurements of acid exposure in the esophagus to be collected on a portable computer. The pH probe is worn for 24 continuous hours. The tube is then removed and the results from the computer are interpreted. These results are compared to what we know is the normal acid exposure in the esophagus. This is considered the "gold standard" for determining if the patient has reflux disease, or GERD.
A special pH-measuring device more recently has been developed that is clipped to the lining of the esophagus, so no tube through the nose into the esophagus is necessary. The pH sensor sends a message to a portable computer that collects data about esophageal acid exposure over 24 hours. The clipped probe in the esophagus slowly detaches itself from the esophagus and is ultimately passed in the stool and discarded.
Impedance is a test is offered at few medical centers. It involves the same type of procedure as a 24-hour pH test (a tube is passed through the nose into the esophagus at the level of the LES). It measures liquid movement from the stomach into the esophagus. This test may be important for people with reflux symptoms who are having bile reflux, not acid reflux, and therefore have normal results from a 24-hour pH probe. Unfortunately, impedance testing cannot be done with the current 24-hour pH-measuring device that is clipped to the lining of the esophagus.
Tests for dysphagia include esophageal manometry, which means that a small tube containing pressure sensors is placed down through the nose into the esophagus to measure the contractions of the esophagus and the relaxation of the lower esophageal sphincter. This test lasts about 30 minutes.
Functional chest pain
The test that is used to determine the cause of chest pain is esophageal manometry – the same test described above to investigate symptoms of food sticking in the chest. Ambulatory pH studies may also be used to see if gastroesophageal reflux may be the cause of the chest pain.