At-home gut tests give inconsistent results, government study finds
Feb 27th 2026
A National Institute of Standards and Technology study sent the same stool samples to seven consumer gut testing firms and found large discrepancies, suggesting current at-home microbiome tests are not reliable for making health decisions.
- Researchers sent identical stool samples to seven direct-to-consumer companies and got markedly different results.
- One company gave contradictory assessments for the same donor sample, calling one result unhealthy and the others healthy.
- Presence of specific bacteria such as Clostridium was reported by some companies and missed by others.
- Variation between companies was about as large as variation between different donors.
- Differences likely stem from sample collection, lab methods, and how results are interpreted.
- Authors say standards and analytical validation are needed before these tests can guide health decisions.