Diagnosis and Tests for GERD
The diagnosis of GERD can often be suspected in a patient's history by the nature of their complaints to a physician, especially if the symptoms are very typical. However, if the patient has atypical/uncommon symptoms, or if the patient and physician need to confirm their diagnosis, there are several tests that the physician may recommend.
This 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. It is not helpful, however, in determining if the patient has mild inflammation of the esophagus or if the patient has Barrett's esophagus (see Endoscopy below). Additionally, a normal esophagram does not exclude the fact that the patient may still have GERD.
This test allows direct visualization of the lining of the esophagus and small intestine by the use of an endoscope passed through the mouth into the esophagus, stomach and small intestine. Direct visualization of the esophageal lining will allow a check for potential damage (esophagitis, ulcers). It will also allow the physician to obtain biopsies for examination to determine if the patient has Barrett's esophagus. In 40-60% of patients with GERD, the endoscopic examination may be normal.
This test 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 will help physicians interpret whether there is a problem with motility of the esophagus or the function of the lower esophageal sphincter. The test by itself does not confirm the diagnosis of GERD but will assist the physician in knowing if esophageal motility problems are contributing to a patient's GERD symptoms.
Ambulatory 24-hour pH probe
This test 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 truly the "gold standard" for determining if the patient has reflux disease. Generally, a pH probe is ordered if the physician is not sure a patient's symptoms are related to GERD or if a patient with GERD has not responded to medical therapy.
More recently, a special pH measuring device has been developed that is clipped to the lining of the esophagus. Since it has an attached pH sensor, 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 data can be printed out to be interpreted and compared to what we know as normal. The clipped probe in the esophagus slowly detaches itself from the esophagus and is ultimately passed in the stool and discarded.
This 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. A 24-hour pH probe reading can be obtained at the same time as the 24-hour impedance measurement. Unfortunately, impedance testing cannot be done with the current 24-hour pH measuring device that is clipped to the lining of the esophagus.