Breath Testing

A Hydrogen and Methane Breath Test can identify if you have an intolerance to common aspects of your diet such as lactose or wheat.

What is a hydrogen/ methane breath test?

The test measures the level of hydrogen and methane in your breath. The pattern and quantity of hydrogen and methane in your breath measured at intervals during the test is analysed. This will help us determine if you are intolerant to sugars or if you have difficulty in processing or absorbing them and, as a result, may suffer from headaches, fatigue, restlessness or irritability or dizziness.

How does it work?

The hydrogen and methane gas in your body is created by bacteria. Some of this hydrogen is absorbed into the bloodstream and then into the lungs where it can be detected in the breath.

When should I consider breath testing?

If you have any of the following symptoms, you may wish to consider testing.

  • Bloating
  • Wind
  • Abdominal cramps
  • Flatulence
  • Rumbling
  • Diarrhoea
  • Nausea

How is the breath test carried out?

We take the first breath hydrogen and methane sample by asking you to breathe out into a handheld device.  This ‘normal’ measurement is compared to the rest. You will then be asked to drink the test sugar solution and provide further samples every 15-30 minutes for the next 2-3 hours. The number of samples taken and the frequency will depend on the results or information we need. At the time each sample is taken, we’ll ask you to rate your symptoms and these will also be recorded. Generally, the test takes between two and three hours in total.

Tests can also be sent out to your home, together with a DVD on how to perform the test at home. You can then undertake the test at your convenience and return the specimen bags to us. A pre-paid label will be enclosed.

A full report will be sent to you within one week of the test.

Are there any side effects?

The test is very safe, and has no significant side effects or risks. As the test involves ingesting sugars, you may experience some symptoms. This usually lasts for only a short time during and following the test.

What happens if the test is positive?

If the test shows that you can’t absorb certain sugars, you may benefit from a formal dietetic and nutritional assessment. This can be arranged by Parkside Hospital, your GP, or by the London Gastroenterology Partnership working in collaboration with the Hospital.

I would like a hydrogen / methane breath test

The test costs £300 (accurate at the time of writing) and you can refer yourself. For the convenience of the Breath Test to be carried out at home a further fee of £35 will be added making a home test cost to be £335.


For more information please call the Day Unit on 0208 605 2888 or email here

This page is intended for information purposes only and should not replace advice that your relevant health professional would give you.