A Gastric Emptying Study (GES) is a medical test that measures the speed at which food travels from the stomach into the small intestine. This procedure, most commonly performed as a nuclear medicine test called scintigraphy, provides objective data on the digestive tract’s motor function, known as gastric motility. Evaluating this rate helps physicians understand the cause of symptoms like persistent nausea, vomiting, or feeling full immediately after eating. The test determines if the stomach is emptying food too slowly or too quickly.
Preparation Requirements
Preparation for a Gastric Emptying Study begins before the appointment to ensure accurate results. Patients are typically required to stop eating and drinking for 6 to 12 hours before the test, often fasting overnight. Maintaining an empty stomach is necessary because unmeasured food can interfere with the standardized test meal.
A physician will discuss which medications must be paused for a few days leading up to the study, as some drugs can alter gut movement. Medications that affect gastric motility, such as opioids, prokinetics like metoclopramide, or some antidepressants, are usually discontinued. Patients with diabetes must consult their healthcare provider for special instructions on managing insulin and blood sugar levels during the fasting period. Smoking is strictly prohibited on the morning of the test, as nicotine slows the rate of gastric emptying.
The Standard Procedure and Time Commitment
The procedure starts when the patient consumes a small, standardized meal labeled with a harmless amount of a radioactive tracer, such as Technetium-99m sulfur colloid. This meal is often a solid food, like scrambled eggs or oatmeal, combined with toast and water, and must be eaten completely within about ten minutes. A specialized gamma camera tracks the tracer’s movement through the stomach.
Immediately after the meal, the first set of images is acquired to establish a baseline of the tracer’s location. The patient returns for additional imaging sessions at set intervals over the next several hours. These intermittent scans are typically performed at the one-hour, two-hour, and four-hour marks following the meal. The actual scanning time is short, usually lasting only a few minutes at each interval.
The total time commitment for the patient is generally four hours, which is the standard duration for solid-meal GES protocols. Between scans, the patient must remain at the facility and refrain from eating, drinking, or engaging in strenuous activity. The four-hour endpoint provides the most sensitive measure for diagnosing delayed gastric emptying.
Interpreting the Study Results
The gamma camera captures the tracer’s location at each time point, allowing a computer to calculate the percentage of the meal remaining in the stomach. A nuclear medicine physician or radiologist analyzes these data points to generate a time-activity curve. This curve shows the rate of emptying compared to established normal ranges.
A normal result indicates that at least 90% of the solid meal has emptied from the stomach by the four-hour mark. If the stomach retains more than 10% of the meal at four hours, or over 60% at two hours, the result supports a diagnosis of delayed gastric emptying, commonly known as gastroparesis. Conversely, a retention rate less than 70% at 30 minutes may suggest rapid gastric emptying, or dumping syndrome. The physician compiles a formal report based on this analysis, which is sent to the doctor who ordered the test. The ordering physician uses this information to discuss the diagnostic outcomes and potential treatment plans with the patient.