Hydrogen Breath Tests

These will require your child to be present at the Outpatient Department for a period of 3 or more hours without having breakfast before arriving. This is because a drink involving an amount of the sugar to be tested for such as sucrose or lactose will be drunk and then if this is not absorbed properly into the gut it will be passed through into the large bowel where normal bacteria present will use the sugar for their growth and as a bi-product use hydrogen. This hydrogen will be absorbed via the gut lining and then it will leave the body in the child’s breath. This can be detected by simply collecting one breath every 30 minutes or so and analysing it for the amount of hydrogen. This is a non-invasive way for looking for sugar malabsorption of various types.

Information for parents

A hydrogen breath test is a way of measuring whether your child is intolerant to certain substances, mainly different types of sugars.

What will happen?

The day before the test your child should not eat any of the following:-

  • Onions
  • Leeks
  • Cabbage
  • Beans
  • Pickled vegetables
  • Chewing gum
  • Vitamins
  • Laxatives
  • Your child should not have antibiotics in the four weeks prior to the test.
  • Your child should not eat anything after supper the night before the test.
  • Your child should brush their teeth thoroughly the morning of the test.

At the outpatients department

When your child arrives at the department to have their hydrogen breath test they will be asked to blow into a hand held machine. It might be helpful to practice blowing at home before the test.

  • Younger children will use a mask over their nose and mouth.
  • Your child will be weighed and then given the prescribed medication in the form of a drink.
  • For the next three hours your child will be asked to blow into the machine every 30 minutes.
  • It may be useful to bring some books or toys to occupy them while they are in the department.
  • When the test is finished they will be able to eat and drink.
  • The results will be sent to your consultant who will discuss them with you in clinic.

Are there any risks?

The chance of any problems occurring is minimal.

The test may give your child stomach ache or diarrhoea as we are giving them a large dose of a substance they do not usually tolerate. Please report any symptoms to the nurse performing the test so your child can be monitored.

Book an appointment

Sign up to our newsletter