SIBO Test Result Interpretation


Experiencing ongoing bloating, abdominal pain, constipation, diarrhoea and gas may indicate an underlying digestive problem. Often people are provided with a blanket diagnosis of irritable bowel syndrome (IBS) although there is no specific test to confirm this. SIBO is commonly underdiagnosed and may be the cause of up 80% of IBS cases. So why does the GP still not test for SIBO? Surely all SIBO sufferers deserve a proper diagnosis so they can overcome their debilitating symptoms, which have a negative impact on their overall health.

So if you are constantly experiencing digestive symptoms after your GP has ruled out everything – my advice would be to get a SIBO test.

Below are two types of SIBO tests you can get.

Small Intestine Aspirate and Fluid Culture

The current gold standard invasive test for SIBO is the small intestine aspirate and fluid culture. The test is performed by passing an endoscope (flexible tube) with a camera through the mouth and throat towards the small intestine, where a sample of intestinal fluid is tested for bacteria overgrowth.

SIBO Breath Test

The SIBO breath test is a non-invasive test which measures the level of hydrogen and methane that you breathe out after the ingestion of either glucose or lactulose solution. The test requires you to blow into a test tube through a straw or into a foil bag. This will provide the baseline reading. Afterwards, you will consume a solution containing either lactulose or glucose within 2 minutes. A breath sample is then taken every 15 minutes between 2 – 3 hours.

The whole purpose of the test is to take a snapshot of how the bacteria in the small intestine are functioning within a 3-hour window. When bacteria digest the food they produce gas. These gases pass through the intestinal wall into the bloodstream; transported to the lungs. The exhaled gases are collected and tested for levels of hydrogen and methane.

SIBO Breath Test Interpretation

A positive SIBO test for hydrogen is considered when there is a rise above 10ppm of hydrogen within 60 minutes or 20ppm of hydrogen within 90 minutes. The reason why there are two cut-off values depends on which part of the world you carry out the test. 60 minutes is the cut-off period in Europe and 90 minutes is the cut-off period in North America.

Interpreting a SIBO test result is not as straightforward as it seems, other factors must be considered. For instance, a reading above 10ppm at 60 mins does not necessarily mean the test result is positive. The result may show a very high ppm from the beginning of the test. If this is the case, this means that you may not have followed the diet, fast or preparation correctly. A SIBO test result showing no hydrogen peak after 90 minutes, potentially means slow gastrointestinal transit or production of hydrogen sulfide.

The importance of working with a practitioner skilled in interpreting SIBO breath tests is vital in getting the correct treatment.

sibo test
SIBO Lactulose Test Result

The above test result indicates that the patient is hydrogen positive according to European and North American guidelines.

How do you order a SIBO test?

You can order a SIBO test through the SIBO clinic or through the many functional testing labs. Any SIBO tests ordered through the SIBO clinic will receive a 5% discount off the 16-week SIBO Breakthrough Programme.