What Is Endoscopic Ultrasound?

What to expect when undergoing this test

An endoscopic ultrasound is a test that helps visualize parts of the digestive tract, such as the stomach, pancreas, and gallbladder, and nearby organs and tissues, such as the lymph nodes. It is performed by using a thin, flexible tube called an endoscope that has a camera and an ultrasound probe on the end. The endoscope is passed down through the mouth or through the anus to have access to the digestive tract organs. The ultrasound is then used to create images of the digestive tract that can be studied for any abnormalities.

Having this test can naturally cause some anxiety. However, it is done under sedation so that patients are as comfortable as possible during the procedure. Because of the sedation, it is usually necessary to take a day off from work or school to have the test. However, this is a test that can give physicians a lot of information about what is going on in the digestive system in certain scenarios, which can help in figuring out why certain signs and symptoms are taking place.

what to expect during endoscopic ultrasound
Verywell/Emily Roberts

Purpose of Test

This test is helpful for seeing parts of the digestive system so it may be ordered to confirm or rule out a suspected digestive disease or a condition. An endoscopic ultrasound will give more detailed information than an X-ray or an external ultrasound. Some of the reasons that this test might be ordered can include:

  • Analyzing and staging cancer of the esophagus, stomach, rectum, or pancreas
  • Investigating a possible cause for abdominal pain or weight loss
  • Evaluating pancreatic conditions such as pancreatitis
  • Investigating abnormalities in the digestive system and other organs, such as tumors
  • Assessing any nodules in the lining of the digestive system

Risks and Contraindications

Serious complications after having an endoscopic ultrasound are rare. For those who have the endoscope inserted into the mouth and down the throat, there can be a sore throat for a few days after. The medical team can give advice on how best to treat that at home and how long it may last.

Biopsies (small pieces of tissue) may be taken during this test and there can sometimes be bleeding at those locations, but it should stop on its own.

More serious, but rare, complications can include having a reaction to the sedatives used during the procedure, infection, and aspirating stomach contents. With any endoscopic test, there is a risk of creating a hole in the digestive tract (called a perforation). If this happens, surgery will be necessary to repair the hole. However, this is rare, even in cases where a fine-needle aspiration is done during the endoscopic procedure.

Several studies that looked at the rates of complications after an endoscopic ultrasound came to the conclusion that it is a very safe procedure. Any unusual symptoms that occur after the test should be discussed with a doctor.

Before the Test

It is necessary to prepare for an endoscopic ultrasound, and a physician will give instructions on how this should be done. When this test is done for the upper digestive tract, it will be necessary to fast for about six hours prior to the start of the procedure. If it is being done on the lower digestive tract, cleaning out the colon with fasting, laxatives and/or enemas will be needed.

Certain medications, such as blood thinners, may need to be stopped for a time before the procedure. It’s important to let the medical team know about all medications currently being taken in order to get instructions on if or when any should be stopped for a time. During a period of fasting, medication that needs to be taken should be swallowed with a small sip of water.

During the Test

This test is usually done in a hospital. The duration of the test varies greatly but usually lasts about one hour.


Patients will be asked to change into a hospital gown and lie on a hospital bed. Nurses and other staff members will take a health history by asking several questions and will provide any forms that need to be signed. An IV will be started to give fluids and to give the sedatives that will make the procedure more comfortable. 

Throughout the Test

Patients are wheeled into the room where the test is to take place. For a lower digestive tract test, patients are asked to lay on their left side. There will be an anesthesiologist and nurses who may attach various monitors in order to monitor vital signs during the test. Some sedation will be given through the IV and the patient will fall asleep for the physician to begin the endoscopy.


Patients will wake up in recovery and will be monitored for a time (maybe about an hour) to ensure that all has gone as expected during the test. Patients should let the staff know if there are any symptoms such as unusual pain or nausea. Ginger ale or water may be given to drink during this recovery time. It may be longer before food is allowed.

After vital signs are stable and it’s clear that there is no concern for any complications, patients are released to go home with a friend or relative. Instructions on going back to normal activity and how and when to take any medications will be given before going home. 

After the Test

Some information about how the test went and initial results may be given directly after the test in recovery. More detailed information and the results of any biopsies that were taken will be available later, usually in about a week.

A follow-up visit with a physician may be scheduled to go over the results of the test and any next steps that are needed. Call a doctor if there are any symptoms after the test such as pain, vomiting, fever, or bleeding.

A Word From Verywell

Endoscopic ultrasound can give so much information about what is happening in the digestive tract. It’s considered to be very safe and it is done under sedation in order to have patients be as comfortable as possible. It may feel stressful to be told that such a test is needed and then undergoing it. Talking with the healthcare professionals about stress levels and worry is important because they can adjust their procedures to help take some of the difficulty out of the situation. Asking questions about the test and how and when results will be available can also help lessen some of the anxiety. 

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  • Hamada T, Yasunaga H, Nakai Y, et al. "Severe bleeding and perforation are rare complications of endoscopic ultrasound-guided fine needle aspiration for pancreatic masses: an analysis of 3,090 patients from 212 hospitals.” Gut Liver. 2014 Mar;8(2):215-8. DOI: 10.5009/gnl.2014.8.2.215.

  • Lakhtakia S. "Complications of diagnostic and therapeutic Endoscopic Ultrasound.” Best Pract Res Clin Gastroenterol. 2016 Oct;30(5):807-823. DOI: 10.1016/j.bpg.2016.10.008.