The FDA maintains it is within the administration's purview to regulate tests--including laboratory-developed tests, or LDTs--although the current state is that the FDA often elects to exercise its discretion to permit LDTs sans regulation-as-medical-device provided the lab adheres to CLIA and has any required accreditation in order.

Dietary supplements are more or less unregulated, as long as they don't claim to diagnose or treat a disease. This is not exactly a great situation for consumers. Also, the current administration has taken sort of a "safety over efficacy" tack, but I don't know, therapeutic failure seems pretty bad, so maybe there isn't that much meaningful difference between the two.

Back to the testing concept, if not for the FDA to come down on operations like Theranos, then who?