DE
Home Offer Breath tests for intolerance H2 lactulose intolerance breath test

Bacterial overgrowth of the small intestine (SIBO - small intestinal bacterial overgrowth)

What is the H2 lactulose breath test?

The H2 lactulose breath test is a diagnostic procedure for the detection of small intestinal bacterial overgrowth (SIBO). This is an excessive colonization of the small intestine with bacteria that normally occur in the large intestine. This incorrect colonization can lead to digestive problems such as flatulence, diarrhoea or abdominal pain.

When is an H2 lactulose breath test useful?

An H2 lactulose breath test is recommended if the following symptoms occur:

  • Flatulence (often shortly after eating)
  • Diarrhea or irregular stool habits
  • Abdominal pain or cramps
  • nausea
  • Nutritional deficiency or unintentional weight loss

The test is often used in patients with irritable bowel syndrome or chronic digestive problems to diagnose bacterial overgrowth in the small intestine.

How does the H2 lactulose breath test work?

The test measures the hydrogen content (H2) and possibly methane (CH4) in the breath after ingestion of a lactulose solution. The procedure is as follows:

  1. Appear fasting: do not eat or drink anything (except water) for at least 12 hours before the test.
  2. Basic breath sample: A first breath sample is taken.
  3. Drink lactulose/glucose: A standardized lactulose solution is taken.
  4. Regular breath samples: breath samples are taken at regular intervals over 2-3 hours.
  5. Evaluation: A rapid increase in the H2 or CH4 concentration indicates bacterial colonization of the small intestine.

Preparation for the test

To ensure that the results are as reliable as possible, patients should observe the following:

  • The day before: do not consume any flatulent foods (e.g. pulses, onions, cabbage) or carbonated drinks.
  • 12 hours before the test: Do not eat anything, only drink water.
  • No antibiotics or probiotics in the last two weeks: These can falsify the test result.

What do the test results mean?

  • Positive test: An early increase in the H2 or CH4 concentration indicates bacterial overgrowth in the small intestine. This means that there are more bacteria there that produce gas and cause discomfort.
  • Negative test: No increased H2 or CH4 concentration means that there is no evidence of bacterial overgrowth.

Treatment of small intestinal colonization

If a small intestinal colonization is diagnosed, the following measures can help:

  • Antibiotic therapy: Targeted antibiotics can reduce the excessive bacteria in the small intestine. In addition to classic antibiotics with a systemic effect (e.g. quinolones, tetracyclines), antibiotics that only act in the intestine and are not absorbed into the blood (e.g. rifaximin, gentamycin/polymyxin) are also used.
  • Change of diet: An adapted diet (e.g. reduction of fermentable carbohydrates, SIBO diet) can alleviate symptoms.
  • Probiotics and intestinal flora management: Long-term optimization of the intestinal flora can help to prevent recurrence of colonization problems.