Explanation

Type of dysbiosis: what is measured?

Based on several measured bacteria, the laboratory places the gut flora in a type of abnormality (dysbiosis), namely putrefactive dyspepsia, anaerobic dysbiosis, gut biome depression or saccharolytic dysbiosis. This is the laboratory's own classification. There is no generally accepted definition of dysbiosis and no recognized classification into types; according to international experts, there is not enough evidence to use such a classification in a test result.

What can it detect?

The composition of the bacteria in the stool at the time of sample collection
Shifts in the gut flora (dysbiosis), a concept with no fixed definition and no established medical significance

Result

What does the result mean?

What the result tells you

The result is a classification that the laboratory made itself, for example based on which group of bacteria is present in larger or smaller amounts than in the comparison group. The type says nothing about a disease and does not explain symptoms. The classification may turn out differently for a next stool sample, because the gut flora changes with diet and medicines. No type on its own calls for a diet, supplements or treatment.

After an abnormal result

For the GP, an abnormal value in the gut flora is usually no reason for further tests or treatment. With symptoms, the GP looks at the symptoms themselves and, if needed, arranges tests according to the guideline, for example for celiac disease, bowel inflammation or a gut infection. According to international experts, the result is not a basis for a diet, supplements or antibiotics.

Reliability

How reliable is the test?

Gut flora testing describes which bacteria are in a portion of stool. It has not been shown that the result helps in making a diagnosis or choosing a treatment, in people with or without symptoms. According to the guideline on irritable bowel syndrome, there is no test that can confirm this condition. An international group of experts concluded in 2025 that there is not enough evidence to use gut flora testing in healthcare, that there are no fixed healthy reference values and that there is no generally accepted definition of dysbiosis. According to the MDL Fonds (Dutch digestive health foundation), too, we do not yet know exactly what a healthy gut flora is; the result is therefore a description, not a medical judgment.

What can affect the result?

The composition differs greatly from person to person and can change from day to day; a second portion of stool can give a different result.
Diet, antibiotics, acid-reducing medicines, laxatives, probiotics and a recent gut infection affect the result.
Methods and reference values are not standardized; results from different laboratories or methods cannot be compared with each other.
Stool mainly shows the bacteria in the last part of the large intestine, not those in the small intestine or on the gut wall.

Who it is for

Who is the test useful for?

Useful for

The result is a description of your gut flora at one moment, with no established medical significance, whether or not you have symptoms. The test is not needed to stay healthy and does not explain bowel symptoms. With bowel symptoms, the GP usually finds the cause through questions and a physical examination, supplemented if needed with targeted blood or stool tests, for example for celiac disease or bowel inflammation. With blood in the stool, unexplained weight loss or new bowel symptoms after the age of 50, this test is no substitute for an examination by the GP.

How common is it?

Because there is no fixed definition of an abnormal gut flora, there are no figures on how common it is. Bowel symptoms without a clear cause are common, though: according to the guideline, irritable bowel syndrome affects about 4 in 100 adults in the Netherlands (by the strictest criteria).

Dutch medical specialists' guideline (FMS) on irritable bowel syndrome (NHG and NVMDL)

Get tested