An electrogastrogram (EGG) is a painless test which measures the electrical activity in the stomach, before, during and after food. This page from Great Ormond Street Hospital (GOSH) explains about the EGG test, what it involves and what to expect when your child has the test.An electrogastrogram (EGG) test is often used in conjunction with other tests to investigate and diagnose stomach problems such as nausea and vomiting.
It uses sensors stuck to your child’s skin to show electrical activity. This is similar to how an electrocardiogram (ECG) measures the electrical activity in the heart. The test takes about three hours and is carried out in the Gastroenterology Investigation Unit (GIU).
What happens before the test?
Your child will need some preparation for the test, but these can be done at home.
Two days (48 hours) before the test
Your child will need to stop taking the following medications 48 hours prior to the test:
- all anti-sickness medications
- all antibiotics including erythromycin and azithromycin
Six hours before the test
Your child should not eat or drink anything (including water) for six hours before the test. It is equally important to keep giving your child food and drink until those times to ensure they remain well-hydrated and get adequate nutrition. We recommend waking your child in the night to give them a drink.
Please bring a high-calorie packed lunch to the hospital for your child to eat during the test. Your child will need to be able to eat the meal within a 30 minute time frame. It must contain foods your child would usually tolerate. The lunch should be at least 10kcal per kg of your child’s weight and ideally contain 30 per cent fat.
For example, if your child weighs 17kg, their meal should contain at least 170 kcal. A 32.5g bag of crisps provides 170kcal and contains 30 per cent fat.
On the day of the test
The person bringing your child to the test should have ‘Parental Responsibility’ for them. Parental Responsibility refers to the individual who has legal rights, responsibilities, duties, power and authority to make decisions for a child. If the person bringing your child does not have Parental Responsibility, we may have to cancel the test.
Please note that some patients will be asked to attend the GIU within Kingfisher Ward, but other patients will need to go to another ward and then be transferred to the GIU.
Once your child is in the GIU, a nurse will check their weight, blood pressure, and heart rate to make sure your child is fit for the procedure.
The nurse will explain the procedure a final time and will answer any further questions. If you are happy to proceed with the EGG test, we will ask you to sign a consent form.
What does the test involve?
The nurse will start by cleaning your child’s tummy with an alcohol wipe and then attach up to six electrodes (which look like round, blue stickers) in specific places. If your child’s stomach is hairy, we will need to shave the area with a safety razor.
The nurse will then attach wires to the electrodes which are joined to a recording machine. Once this equipment is in place, the test will start approximately 15 minutes later – this is because the gel part of the electrodes need time to soak into the skin. This does not hurt. A few children are allergic to the electrode stickers, so if your child has any allergies, please tell the nurse at the start of the test.
Your child will need to lie or sit very still. Watching TV or reading a book together may help. However there can be no electrical equipment including mobile phones, tablet computers or portable DVD players near your child’s stomach.
After an hour, your child will have 30 minutes to eat the high calorie packed lunch you brought with you, and then the test will continue for another hour after they finish eating.
Are there any risks?
This test is very safe with the only potential risk being an allergy to the electrodes. However, this is not usually serious but can make their skin a bit itchy.
What happens after the test?
The nurse will remove the electrodes from your child’s tummy and your child can return to the ward or go home.
When you are at home
Please re-start your child’s medicines as before. Your child can return to their usual food and drink.
If there is any sticky residue from the electrodes left on the skin, it can be washed off with soap and water.
If you have any questions, please telephone the Gastroenterology Investigation Suite on 020 7405 9200 ext 0212. Out of hours or in an emergency, please contact NHS 111 or take your child to the nearest Accident and Emergency (A&E) department.
How long will it take to get the results?
Your child’s test results will be given to you at your next outpatient appointment at the hospital. If there is a need to start on new treatment before the appointment, the hospital will contact both you and your family doctor (GP) with details.