Gastric Emptying Tests

What are gastric emptying tests?

Gastric emptying tests measure the time it takes for food to empty out of your stomach. After a meal, it usually takes around four hours for 90 percent of the food to move out of your stomach and into your small intestine. But if your stomach empties too fast or too slow, it could be a sign of a health issue.

When your stomach empties too slowly (longer than normal), it may be a sign of delayed gastric emptying, called gastroparesis. It's often difficult to find the cause of gastroparesis, but diabetes is the most common underlying cause since it can damage some of the nerves in your stomach. Other causes of gastroparesis can include:

• Hypothyroidism
• Injury to your esophagus (the muscular tube that carries food and liquids from your mouth to the stomach), stomach, or small intestine during surgery
• Certain autoimmune diseases
• Nervous system disorders such as Parkinson's disease and multiple sclerosis
• A viral infection of your stomach

If food stays in your stomach for too long, it can harden into a solid mass called a bezoar. A bezoar may lead to a dangerous blockage that prevents food from passing into your small intestine.

Gastroparesis may also cause malnutrition (not getting enough nutrients from your food).

When your stomach empties too rapidly (faster than normal), it may be a sign of dumping syndrome. Dumping syndrome happens when your stomach empties food too quickly into your small intestine. It is usually associated with surgery on your stomach (such as weight loss surgery) or your esophagus.

• If you have symptoms such as diarrhea, bloating, or nausea within 30 minutes after eating, it may be a sign of early dumping syndrome, which is more common than late dumping syndrome.
• If you have symptoms such as feeling light-headed, tired, or a fast heartbeat within one to three hours after eating a meal, it may be a sign of late dumping syndrome.

Gastric emptying tests may help you get treatment for gastroparesis and other digestive system issues before they cause serious complications.

Other names: gastric emptying study, gastric emptying scan, gastric emptying scintigraphy, smart pill, wireless motility study, gastric emptying breath test, upper GI series, barium swallow

What are they used for?

Gastric emptying tests are most often used to diagnose gastroparesis. They may also be used to check for other problems with food passing through your stomach.

Why do I need a gastric emptying test?

You may need this test if you have symptoms of gastroparesis, which include:

• Abdominal (belly) pain
• Bloating
• Nausea and vomiting
• A feeling of fullness after just a few bites of food
• Loss of appetite
• Weight loss

What happens during a gastric emptying test?

Gastric emptying tests are most often done by a radiologist or radiology technician. A radiologist is a doctor who specializes in using imaging tests to diagnose and treat diseases and injuries. There are different types of tests. You may have one or more of the following tests:

Gastric emptying study, also known as a gastric emptying scan, or gastric emptying scintigraphy. This is the most common test used to diagnose gastroparesis. During this test:

• You will start by eating a light meal, often eggs and toast. The food will contain a small, harmless amount of radioactive material called a tracer.
• After you finish eating, you will lie down on an x-ray table.
• The radiologist will take images of your abdomen using a scanning device.
• The radiologist will watch the movements of the radioactive tracer on a monitor. The tracer will show how food travels through your stomach.
• Additional images will be taken over the next few hours to see how long it takes for food to move out of your stomach and into your small intestine.
• You can get up and leave the exam room during this time. Your provider will let you know when you need to return for imaging. It's usually at around 1, 2, and 4 hours after the first image was taken.

A gastric emptying study may also be done using a liquid containing the radioactive tracer instead of solid food. Since liquids move through your stomach differently, your provider may want to perform a liquid gastric emptying test with your gastric emptying study or as a follow-up.

Upper GI series, also known as a barium swallow. During this test:

• You will swallow a chalky-tasting liquid that contains barium. Barium is a substance that coats your internal organs and tissues so they can be seen more clearly on an x-ray.
• You will lie on an x-ray table.
• A special type of x-ray called a fluoroscopy will track the barium in real-time as a live video as it moves through your esophagus, stomach, and small intestine.
• You may be asked to hold your breath at certain times.
• You may be asked to change positions while more images are taken.

Gastric emptying breath test. During this test:

• You will eat a meal or drink a liquid that contains a type of protein that your body absorbs. The substance eventually passes into your breath.
• A provider will collect samples of your breath over a period of about four hours.
• You may be able to leave the exam room during this period but must sit quietly. You should not smoke or eat while you wait. Your provider will let you know when you need to return for imaging.
• The amount of substance in your breath samples can help show how fast your stomach has emptied.

Smart pill, also known as a wireless motility capsule. During this test:

• You will swallow a smart pill, a pill-sized wireless electronic device.
• You will then proceed with your normal daily activities.
• As you go through your day, the smart pill will travel through your gastrointestinal system and collect data.
• The data is sent to a receiver you wear, usually around your waist.
• After a day or two, the smart pill will leave your body in a bowel movement (poop).
• You may not feel it when the smart pill exits your body. So when you have a bowel movement, wait 3 minutes before flushing. This will ensure the receiver you wear on your body captures the data, even after the capsule leaves your body.
• After 4 or 5 days, you will return the receiver to the radiologist, who will review the results.

Will I need to do anything to prepare for the test?

You may need to fast (not eat or drink) for several hours before your test. Your provider will also let you know if you need to stop taking certain medicines before your test.

Are there any risks to the test?

You should not have a gastric emptying study or an upper GI series if you are pregnant or think you may be pregnant. Radiation from these imaging tests can be harmful to a developing baby.

For others, there is little risk to having an imaging test. The dose of radiation is very low and not considered harmful for most people. But talk to your provider about all the x-rays you've had in the past. The risks from radiation exposure may be linked to the number of x-ray treatments you've had over time.

If you're having an upper GI series, tell your provider if you have any known allergies to the barium used in the test. Also, your poop may look white for several days after the test as you pass the barium. You may have constipation if all the barium doesn't pass out of your body.

There is very little risk to having a gastric breath test or taking a smart pill. In rare cases, a smart pill may get stuck in your digestive system. If the pill takes longer than several days to leave your body in a bowel movement, contact your provider.

What do the results mean?

If your results show it took a longer-than-normal time for your stomach to empty, it could mean you have gastroparesis.

If your results show it took a shorter-than-normal time for your stomach to empty, it could mean you have dumping syndrome.

If you have questions about your results, talk to your provider. Your provider may also consider your symptoms and medical history to understand your results.

Is there anything else I need to know about gastric emptying tests?

Treatment for gastroparesis may involve taking certain medicines and/or treating the condition causing the problem, such as diabetes.

Regardless of the cause, your provider will likely recommend changing your diet and eating habits. These may include:

• Eating foods low in fiber and fat.
• Avoiding carbonated drinks, smoking, and alcohol.
• Eating smaller meals throughout the day rather than two or three large meals.
• Chewing food thoroughly.
• Waiting at least two hours after eating before lying down.