Breath Tests and SIBO
The only solid diagnosis for SIBO at the time of this writing is culture and analysis of fluid aspirated (drained) from the jejunum. Otherwise known as the second part of the small intestine.5,6
Note that this is not a procedure that is available to patients. In fact, only research centers offer it. Biopsy of the jejunal lining is a procedure that is available during an endoscopy. However, it is not as accurate.7
The most popular test in use measures the amount of hydrogen or methane in the breath. The availability of breath testing has driven the popularity of the diagnosis of SIBO and the confusion about its treatment.
Before the test, the administrator of the test gives the person tested an oral measured dose. This dose includes lactulose, glucose, xylose, or sucrose to provoke the bacteria.
When people with suspicious symptoms are tested for SIBO, how many have it? The range can be as large as 4% to 78%.
What if you test people with no digestive symptoms? In healthy people, the number of ‘have SIBO’ is anywhere from 1% to 40%.8
Why are these ranges so large? It depends on which challenge agent is used, how large of a dose is given, how frequently the tests are done, how soon the tests are started, and what you define as abnormal levels.
There are many different ways the tests are done. Furthermore, none are validated as being superior to others.
There is also a high rate of random variability within the same person. One study saw that 67% of people tested get different results when retested 6 weeks later even though they were given no treatment or dietary change.9
Other studies have shown that as many as 29% of people who fail a breath test have a normal test on a repeat without any treatment.10
What’s the best way to remedy SIBO? Just do your test over. The chances are that you’ll likely get a different result.
SIBO Tests Don’t Predict Symptoms
When comparing the same types of tests, things don’t get better.
The other assumption in the SIBO hypothesis is that SIBO tests show results that are not present in people without IBS symptoms.
This assumption is also not true.