The crazy thing about Theranos is that so many people with experience in microfluidics (developed mainly for DNA sequencing although there are other uses) knew that their claims were impossible, technologically speaking. Working with such small volumes to obtain quantitive estimates of blood chemistry is so implausible, as you are introducing uncontrollable variability - micro-evaporation, even tissue localization is…
In the documentary, they focused a lot on the engineering challenges of the machine they were making. The blood samples would spill, which would gum up the mechanical workings of the machine and make a huge mess and contaminate all the other samples. The documentary claimed that Theranos started doing demos where they would pretend to put the blood samples into the machine, but really take it to a lab bench and run the tests there, and then report the results back.
That implies to me that at least some of their tests were actually possible to do. I left the documentary thinking "someone should simply do this again, solve the mechanical/robotics problem, and not lie about it and this could still be a game changing technology". But then I've seen other sources (like your comment here) claiming that the basic science of what they were trying to do was impossible/fraudulent from the beginning.
Which is true?