Well, depends on how you define ‘heavily’. Theranos did hide a lab, but even beyond that they were depending on rules that allowed novel tests with very minimal oversight, provided they were done in a lab rather than in the field.

(Also, the regulator was presumably aware that Theranos made proprietary medical devices; it said so on their website. So, when they were shown a lab full of Siemens stuff, they should probably have asked about that. The problem here was really hiding in plain sight, and a competent, sufficiently empowered regulator would have caught it)