DTC microbiome testing: a plea for regulatory safeguards
The medical potential of microbiome appears to have opened the door to a lucrative market: self-diagnosis. However, a lack of safeguards has led to misleading claims, as well as risks for patients ready to do anything to reduce suffering from chronic disease.
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About this article
In recent years, research has highlighted the health potential of the microbiome, leading to a burgeoning market for DTC tests that promise consumers the best of everything. Researchers and clinicians in the US are questioning these claims, and in an article published in Science, they have thoroughly examined the online services and promises of 31 companies, 17 of them based in the United States. These services mainly relate to the gut microbiota and to a lesser extent to the vaginal and skin microbiota.
Similar to DNA testing
In practical terms, these tests resemble DNA tests: you order a kit, take a sample and return it to the laboratory where it is sequenced to determine the taxonomic composition of the microbiome. The customer receives a report, often in graphic format, and a verdict (healthy microbiome or dysbiosis) obtained via comparison with databases with questionable representativeness. If a dysbiosis is detected, the customer is given recommendations, as well as the offer of dietary supplements sold by 45% of the companies marketing these tests. Predictably, they are also recommended regular tests to monitor improvements.
63% of the world’s population think it would be useful to test their gut microbiota
Tests with no validity or usefulness
For the authors of the article, the three requirements guaranteeing the accuracy and usefulness of a test have not been met:
- analytical validity (false-positive and false-negative rates) cannot be guaranteed: the bacterial microbiome has not yet been fully deciphered, the test does not analyze all bacteria, results vary from one laboratory to another or even within the same laboratory (non-standardized methods, variable databases, etc.);
- clinical validity (healthy or dysbiotic microbiome?) is doubtful, given the lack of a standard for “healthy” microbiota;
- clinical usefulness is questionable, since the information obtained does not allow for recommendations or treatment.
To be sure, many companies are careful to point out that their tests have no “diagnostic” value. However, their marketing suggests otherwise, especially since the results give the impression of being scientific.
Opportunity cost for patient
If they lead to misdiagnoses, delays in treatment, or discontinuation of treatment in favor of alternatives with no proven benefit, these tests can have devastating effects for patients with a serious chronic illness. One patient even planned to perform a homemade fecal transplant. The authors of the article thus highlight the need for regulations requiring companies that market these tests to specify their methodology, adopt future standards, and publish test performance, and prohibiting false or misleading claims and promises. The fact remains, however, that further research is needed to characterize a healthy microbiome and confirm whether or not dietary changes and/or supplements are effective.
