When it comes to biotech companies working in clinical diagnostics, lacking the proper credentials is way WORSE than 'none of these tests work.' Most diagnostics companies self regulate by hiring an FDA certified lab managers and technicians who share responsibility for making sure that the marketed product, in this case blood tests, is properly carried out and that it is comparable to the gold standard (usually much more expensive tests with known performance and false negative/positive rates). The FDA set it up this way because otherwise regulating all of the labs and their output like pharmaceuticals would be insanely more expensive and wildly impractical.

A company like Theranos selling blood tests without properly certified staff is the equivalent of Genentech or Pfizer marketing and selling snake oil disguised as cancer medication. It's the equivalent of selling something without having ever tested it to begin with.