Gastroesophageal reflux disease (GERD) occurs when stomach contents flow back up into the esophagus, causing uncomfortable symptoms and potential complications. This backwash contains stomach acid, bile, and digestive enzymes that irritate the lining of the food pipe. While occasional heartburn is common, GERD is diagnosed when these reflux episodes are frequent or severe enough to cause chronic symptoms or damage the esophagus. When initial treatment fails, or if a patient’s symptoms are persistent, severe, or atypical, objective testing is typically required to confirm the diagnosis and determine the extent of the disease.
Initial Assessment Based on Patient History
The diagnostic process begins with a thorough review of the patient’s medical history and a physical examination. Doctors focus on the frequency and nature of typical symptoms, such as heartburn (a burning sensation behind the breastbone) and regurgitation. The presence of “alarm symptoms,” including difficulty swallowing (dysphagia), unexplained weight loss, gastrointestinal bleeding, or persistent vomiting, immediately prompts the need for more invasive testing.
For patients with classic GERD symptoms but no alarm features, the doctor may recommend an initial trial of empirical therapy. This involves prescribing a proton pump inhibitor (PPI), a medication that reduces stomach acid production, usually taken daily for four to eight weeks. If symptoms resolve entirely during this period, acid-related GERD is often presumed. If the patient’s symptoms show only a partial response or no response to this initial PPI trial, objective diagnostic procedures are necessary.
Direct Visualization through Endoscopy
One of the first objective tests performed is an Upper Gastrointestinal Endoscopy (EGD). This procedure involves passing a thin, flexible tube (an endoscope) equipped with a camera through the mouth and down into the esophagus, stomach, and the first part of the small intestine. The EGD’s primary purpose is to visually inspect the lining of the upper digestive tract for damage caused by chronic acid exposure, rather than detecting reflux as it happens.
During the endoscopy, the physician looks for inflammation of the esophagus, known as esophagitis, which is graded based on severity. They also check for complications like peptic strictures (narrowing of the esophagus) or ulcers. The doctor searches for signs of Barrett’s esophagus, a precancerous condition where the normal esophageal lining is replaced by intestinal-like tissue, which is a significant complication of long-term GERD.
Small tissue samples (biopsies) are often collected during the procedure, even if the lining appears normal. These samples are examined under a microscope to confirm the nature of any inflammation, check for cellular changes indicative of Barrett’s esophagus, or rule out other conditions mimicking GERD. The EGD also provides information about the presence of a hiatal hernia, where a portion of the stomach pushes up through the diaphragm.
Quantifying Reflux with Monitoring Tests
Ambulatory monitoring tests are used to measure the frequency and duration of reflux episodes, confirming a GERD diagnosis. One common method is 24-hour catheter-based pH monitoring. A thin, flexible tube is passed through the nose and positioned in the esophagus to measure acid exposure over a day. This test records the percentage of time the esophageal pH drops below 4, which is the threshold for significant acid reflux, and correlates these drops with the patient’s reported symptoms.
An alternative method is the wireless Bravo pH capsule, a small device attached to the esophageal lining during an endoscopy. The capsule eliminates the need for a nasal catheter, improving patient tolerance and allowing data recording for up to 96 hours. This extended monitoring provides a more representative picture of the patient’s reflux burden during their normal daily routine, which can be affected by the discomfort of a catheter-based system.
For patients whose symptoms persist despite maximal acid suppression with PPIs, or those whose symptoms may be non-acidic, doctors use Esophageal Impedance testing. This technique is typically performed alongside pH monitoring, known as combined impedance-pH monitoring (MII-pH). Impedance sensors detect the movement of liquid and gas within the esophagus, allowing the doctor to identify and quantify all types of reflux episodes: acidic, weakly acidic, and non-acidic events. This comprehensive measurement is useful for diagnosing patients with reflux hypersensitivity or non-acidic reflux, which pH-only studies would miss.
Assessing Esophageal Muscle Function
When symptoms like difficulty swallowing are present, Esophageal Manometry is performed to evaluate the mechanics of the swallowing process. This test uses a high-resolution catheter containing multiple pressure sensors, passed through the nose into the esophagus. Manometry measures the strength and coordination of the muscle contractions (peristalsis) that move food down the esophagus.
The manometry also provides precise measurements of the pressure exerted by the Lower Esophageal Sphincter (LES), the ring of muscle at the junction of the esophagus and stomach. A weak or poorly relaxing LES is a common cause of GERD. This test is also used to rule out primary esophageal motility disorders, such as achalasia, which can present with symptoms similar to reflux. The information gathered helps accurately locate the LES, guiding the proper placement of pH or impedance probes for reflux monitoring.
A complementary procedure is the Barium Swallow (or esophagram). The patient swallows a chalky, contrast liquid that coats the inner lining of the upper digestive tract, and X-ray images are then taken. This allows the doctor to observe the shape and structure of the esophagus and stomach. The test is useful for identifying structural abnormalities like a large hiatal hernia or narrowing (strictures) that affect food passage, but it is not used to confirm the presence of acid reflux itself.