Longer answer: Theranos never really got their own custom machines working. Until those machines were working, they did use other machines and processes which did work. However, their entire shtick was trying to do a lot of tests on less blood than usual, so... they simply diluted the blood samples to get enough volume for those machines to function in the first place, and correspondingly, the results were absolute garbage. Effectively, they were using working machines incorrectly to cover up for their non-working machines.