The gastric emptying study is the most commonly used test to diagnose gastroparesis. There are several variations of the test depending on which medical center performs it.
For this test, the patient is instructed to not eat or drink anything after midnight the night before and to avoid certain medications the day of the test. Some meds can affect the accuracy of the test results.
Before the test:
Before the test, the patient is given a meal with a trace of radioactive markers in it. The most common food used is eggs and toast, but often oatmeal or other foods are provided. A small amount of water or juice may also accompany the meal. This meal should be eaten within a certain timeframe in order to ensure the most accurate results.
During the test:
The GES typically lasts anywhere from 90 minutes to 6 hours. Images of the rate at which the food is digested are taken at certain intervals, often at the first half hour, then every half hour-hour after that. In most instances, the patient is allowed to return to the waiting room in between images. It is believed that the 4-6 hour tests are the most accurate. Many people may have normal results with the 90 minute test, but show delayed emptying during the 4-6 hour version.
After the test:
Nothing is required after the test is over. The patient may return to normal meds, activity, and eating as instructed by his/her physician. Test results may take a couple of days to analyze.
A negative result means the meal moved through the stomach at a normal rate and is not suggestive of gastroparesis. If the results are positive, gastroparesis is the first suspicion and the physician may request additional testing to rule out additional causes for delayed emptying such as blockages, certain medications, or tumors.