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Gastric Reflux Test (Multichannel Intraluminal Impedance Test)

What is a Gastric Reflux Test (Multichannel Intraluminal Impedance Test)?

The Gastric Reflux Test (Multichannel Intraluminal Impedance Test) is used to detect and record the number of times stomach contents come back into the esophagus and the relation of these episodes to symptoms (when a child cries, arches, coughs, gags, vomits, has chest pain, etc.). It also determines whether or not the contents are acidic and how long they stay in the esophagus.

The test is performed using a thin light wire containing an acid sensor, and six to seven metal sensors. It is inserted through the nose into the lower part of the esophagus. The impedance probe is then connected to a recorder box that the patient will carry with them for the duration of the study.

Before the Test

The child shouldn't have anything to eat or drink two hours before the procedure if inserted while the child is awake. Standard endoscopy prep time is used if patient is undergoing anesthesia for procedures.

The procedure is explained to the patient in detail prior to inserting the wire. Each action is explained to the child before it's performed. Questions can be answered after the wire is placed. Child life staff may be a useful resource to aid the patient and staff during placement of the probe, as this can be an uncomfortable procedure while awake.

During the Test

The nurse will insert the wire into the child's nose and down the esophagus until the desired depth is reached. The wire will be secured to the patient’s face with tape. This can take place at the bedside or in the operating room under anesthesia with other procedures.

An X-ray will be performed to verify proper placement of the impedance probe. Small adjustments to the probe placement may be indicated. After proper placement is confirmed, the study will record for approximately 23 hours. The child will remain admitted to the hospital for observation but may go about their daily routine as allowed by his / her physician.

Family participation is expected during the test. A parent or other adult will need to push a button on the recording device when the patient eats a meal, lies down, or is actively having symptoms. This information will help the healthcare team better analyze the test results.

After the Test

Once the probe is removed on the second day, the information collected in the recorder box will then be downloaded onto a computer, edited and analyzed.

A physician will look at the report created from the data and discuss findings with the patient and family within approximately two weeks.

Diet and Activity

The child should not drink carbonated or acidic drinks such as orange juice, soda, etc.

The child should avoid chewing gum and hard candies which can cause an increase in swallowing.


There are no restrictions on activity related to the test.

Last Updated 06/2023

Reviewed By Lisa Paxton, APRN
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