A gastric emptying scan (GES) is a medical test used to diagnose digestive conditions. It is also called a gastric emptying study or gastric emptying scintigraphy.
A gastric emptying study is a nuclear medicine test, meaning it uses small amounts of radiation. It is usually done in the Nuclear Medicine department of a hospital as an inpatient or outpatient test.
This article will go over why you may need this test, how a gastric emptying study is done, and what the results mean.
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Purpose of Test
A gastric emptying scan may be ordered to help your healthcare provider determine the cause of a number of symptoms involving the digestive tract.
You might need to have a gastric emptying study done if you have:
- Abdominal pain
- Nausea and vomiting
- Feeling full after eating only a small amount of food
- Unintentional weight loss in adults
- Suspected gastroparesis
- Failure to gain weight (in children)
- Suspected rapid gastric emptying, or dumping syndrome (food moves through your stomach too fast)
A gastric emptying study can also be used:
- As prep for certain surgical procedures such as a colectomy
- To evaluate for gastroesophageal reflux disease (GERD), particularly reflux that has been unresponsive to therapy
Risks and Contraindications
Before having a gastric emptying scan, tell your healthcare provider about any food or medication allergies you have. You will be instructed to stop eating and drinking for about four hours before the test. It is important to follow these instructions to ensure accurate test results.
Medications
Some medications need to be stopped before a gastric emptying scan. For example, your provider may tell you not to take any medication that changes how your stomach processes food.
This list is not all-inclusive, but here are a few medications that should be discontinued before a gastric emptying study:
- Metoclopramide
- Erythromycin
- Tegaserod
- Domperidone
- Narcotic pain relievers such as oxycodone, hydrocodone, morphine, and more
- Atropine
- Dicyclomine
- Loperamide
- Promethazine
Health Conditions
Having certain health conditions may mean you need different instructions for a gastric emptying scan. For example:
- If you have diabetes and use insulin, you will be given instructions about managing your glucose levels on the day of the test. Your insulin dose might need to be adjusted.
- If you are menstruating, having the test done during days one to 10 of your monthly cycle may provide more accurate results because hormonal changes affect how fast the stomach normally empties.
Radiation
Some individuals may be concerned about being exposed to radiation during this test since radiation exposure has been linked to cancer. It is thought that infrequent low doses of radiation typically used for medical procedures pose minimal risk.
The biggest factors that contribute to radiation cancer risk include:
- The amount of radiation you are exposed to
- The length of time you are exposed to radiation
- The frequency of radiation exposure (having the test only one time versus having many tests or procedures that use radiation)
A gastric emptying test, however, is not generally recommended for pregnant women because of the potential risk to the fetus. Breastfeeding women can have a gastric emptying study, but they are advised not to breastfeed for a brief period after the scan.
The risk-to-benefit ratio should also be considered when giving the test to children. If you are concerned about radiation exposure, discuss it with your healthcare provider before scheduling a gastric emptying scan.
Alternatives
If you can't have a gastric emptying scan, your provider might recommend doing a different test. Alternatives to a gastric emptying study include:
- Barium swallow test: For this test, you will drink a beverage that has a substance called barium in it. The substance is safe for you to drink and helps your insides "light up" on a special kind of X-ray. The test can be used to look for problems in your esophagus and stomach.
- Breath test: For this test, you will swallow a substance containing urea that will help show if you have H.pylori bacteria in your stomach. When the urea gets into your stomach, it will react with any H.pylori bacteria, which will make carbon dioxide (CO2). When your breath is measured, your provider can see if there is CO2 in it.
- "Smart pill" or capsule test: For this test, you will swallow a little pill that has a camera inside it. As it moves through your digestive tract, it will take some pictures. The pill with the camera leaves the body when you have a bowel movement (poop). Your provider can use it to see if you have certain problems in your stomach or intestines, like ulcers or strictures (narrow sections).
You cannot have a barium test within 48 hours of having the gastric emptying test.
Gastric Emptying Study Prep
Your healthcare provider will give you instructions to follow before a gastric emptying test.
Before the test, you will have something to eat. If your provider orders solid food before your scan, the standard meal consists of scrambled egg whites, toast with jam, and a small glass of water.
The meal must be the same to ensure the test results are accurate. The scrambled egg whites contain a radioactive isotope called Technetium-99m Sulfur Colloid which is tasteless. If possible, this meal should be eaten within 10 minutes.
Children
If your child is having a gastric emptying scan, explain what will happen beforehand to help alleviate any anxiety they may have. It can also be helpful to bring a comfort item such as a favorite toy or a blanket on the test day.
Most children's hospitals have staff who specialize in relieving a child's anxiety and discomfort during medical tests. Don't hesitate to request these kinds of services when you arrive.
During the Test
After you finish eating, you will lie down on a table. Then, images of your abdomen will be taken with a special camera. The pictures are taken at various time intervals to see how much of the food has been eliminated from the stomach and how long it takes.
During a gastric emptying study, images will be taken 30 minutes, one hour, two hours, and four hours after you have eaten the meal. The scan is not usually painful or uncomfortable.
You may be allowed to leave the nuclear medicine department and return in time to have more images taken at these various times. This means that the whole gastric emptying test takes four and a half to five hours.
Sometimes a liquid meal is ordered instead of a solid meal. This may be because of the specific condition that your healthcare provider is trying to diagnose with the test or simply because the test is being done on an infant or individual who normally consumes a liquid diet.
In this case, the test procedure is similar but the radioactive isotope is added to water, formula, or milk and the intervals for taking pictures are much closer together.
How Long Does a Gastric Emptying Study Take?
The overall time the test takes is typically much shorter when using a liquid diet compared to a solid diet (approximately one hour versus four hours or more).
Gastric Emptying Study Results
Certain factors can limit how accurate gastric emptying study results are. These include poor blood sugar control if you are diabetic, not finishing your meal within the 10-minute time frame or not finishing the meal completely, and vomiting during the test.
How Long Does It Take to Get Results?
The amount of time it takes to get the results of a gastric emptying scan varies. A specialist called a radiologist generally interprets the images and then writes a report that is given to your healthcare provider.
Interpreting Results
When you get your results, you will see each time you had a picture taken throughout the test and a percentage. The percentage shows how much of the meal you ate before the test was still in your stomach each time an image was captured.
Normal gastric emptying study results are typically considered:
- 30 minutes: More than or equal to 70% of the meal is still in your stomach
- One hour: 30% to 90% of the meal is still in your stomach
- Two hours:Less than or equal to60% of the meal is left in your stomach
- Four hours:Less than or equal to10% of the meal is left in your stomach
If your results are different, it will mean that food either leaves your stomach faster or slower than normal. Your provider will look at how much food was left in your stomach each time to see how far your results are from normal results. This will help them figure out what might be causing your symptoms.
You might have gastroparesis if:
- More than 60% of the meal is still in your stomach after two hours.
- More than 10% of the meal is still in your stomach after four hours.
You might have dumping syndrome (rapid gastric emptying) if:
- More than 30% of the meal has already emptied after 30 minutes.
- More than 70% of the meal has already emptied after an hour.
Summary
A gastric emptying study can be used to diagnose digestive conditions. The test involves eating a meal that has a special substance in it called barium that helps the organs show up better on an imaging scan.
The pictures show how long it takes for food to move out of the stomach. Some conditions cause the stomach to empty too slowly and others cause it to empty too fast.
Providers can use a gastric emptying study to diagnose conditions like gastroparesis and dumping syndrome.
Frequently Asked Questions
What does a gastric emptying study diagnose?
A gastric emptying study helps diagnose certain health conditions that can make your stomach empty faster or slower than usual, such as gastroparesis and dumping syndrome.
Is a gastric emptying study painful?
Having pictures taken with an X-ray during the test won't hurt. However, you might feel uncomfortable because of the meal you have to eat before the test.
How much does a gastric emptying study cost?
According to a database managed by Fair Health Consumer, a group that assesses data from health insurance claims nationwide, the average cost for an uninsured patient who has the test done at a surgical center is in the $1,000-$2,000 range. Insurance coverage and your location factor into what you'll pay.
What Does Gastroparesis Feel Like?
