Gastric Emptying Study (GES) is one of the diagnostic tools used to diagnose Gastroparesis (GP). GES is sometimes referred to as Gastric Emptying Scan or Gastric Emptying Scintigraphy. A GES test is requested by your Gastroenterologist (GI doctor) or Primary Care Physician (PCP) to determine if you have GP and the severity of your GP. GES is performed by a nuclear medicine doctor or technician.
To prepare for your GES test, your doctor may recommend that you stop taking some of your medications several days (48-72 hours) prior to the test. Medications that need to stop include narcotic pain medications, calcium channel blockers, prokinetic agents, and proton-pump inhibitors (PPIs). These medications impact digestion and may skew your test results. You may also be required to fast (NPO) 8 to 12 hours before the test. Check with your doctor for specific instructions.
Right before the GES, you will eat food that includes tasteless radioactive material – usually eggs and toast with jelly or oatmeal and a small amount of water. The scanner follows the radioactive material as your stomach digests the food. The scan usually lasts four hours, although some doctors request a two-hour or six-hour test. Scans are completed every 30 minutes. No food or drink is permitted during the scan. Don’t worry about the radiation. It’s a very small amount and is not absorbed into your body. Please let your doctor know if you are pregnant or diabetic prior to the test.
GP is diagnosed when the radioactive food remains in the stomach through duration of the GES. Delayed emptying determined when test results show that there is less than 10% emptying at 1 hour, less than 40% emptying at 2 hours, and less than 90% emptying at 4 hours. Severity is determined by the percentage remaining in your stomach after 4 hours. For example, if results appear as follows – percent gastric emptying was 13%, 34%, 48%, and 71% at 1, 2, 3, and 4 hours post-ingestion, respectively – this means that there is 29% remaining in the stomach at the end of 4 hours. This patient in the above example would be diagnosed with moderate GP.
Your GI or PCP may also order a Gastric Emptying Liquid Study. As with the solid study, your doctor may request that you stop certain medications and fast prior (NPO) to the test. The liquid study is 90 minutes in duration. You will drink water that contains a tasteless radioactive isotope. Scans will commence one minute after drinking the water, at 30 minutes and at 60 minutes. Normal gastric half empty time is less or equal to 23 minutes. Anything more than 23 minutes would indicate delayed emptying for liquids from the stomach to the small bowel.
Discuss your GES findings and treatment plan with your GI or PCP.