Incidentally, the book does contain a lot of discussion about patents. Holmes offended a longtime family friend, Richard Fuisz -- who, incidentally, was a former CIA agent -- around 2005-2006. He was mad Holmes and her family never consulted with him about the Threanos idea, so he wrote his own patent (made public on Jan 3, 2008) that he described as "the Theranos killer". It turned into a big legal battle that caught the eye of a Fortune writer, who ended up writing the first big magazine cover story on Holmes/Theranos:
http://fortune.com/2014/06/12/theranos-blood-holmes/
The whole subplot is quite remarkable. Fuisz's battle with Theranos led to some damaging testimony in deposition. Fuisz's son became determined to take down Theranos and from what I can tell, had a big (but mostly unknown) part in the unraveling of Theranos. He found in a Google search a blog post [0] (now taken down) that made serious accusations about Theranos after the New Yorker cover story.
Joe Fuisz, Richard's son, ended up contacting the blog author and telling him about the Fuisz vs. Holmes fight [1]. This blog author ended up contacting a WSJ reporter that he had previously worked with, John Carreyrou.
So rather than science/engineering directly leading to Threanos's downfall, it seems a personal spat played a bigger part. And ironically, this spat involved a guy who wanted to out-patent-troll Elizabeth Holmes.
An excerpt from the book about what started Richard Fuisz's feud:
Richard Fuisz was a vain and prideful man. The thought that the daughter of longtime friends and former neighbors would launch a company in his area of expertise and that they wouldn’t ask for his help or even consult him deeply offended him. As he would put it years later in an email, “The fact that the Holmes family was so willing to partake of our hospitality (New York apartment, dinners, etc.) made it particularly bitter to me that they would not ask for advice. Essentially the message was, ‘I’ll drink your wine but I won’t ask you for advice in the very field that paid for the wine.’ ”
Carreyrou, John. Bad Blood: Secrets and Lies in a Silicon Valley Startup (p. 71). Knopf Doubleday Publishing Group. Kindle Edition.
[0] edit: Here's an archive snapshot of the now taken down blog post: http://archive.is/BGtRJ
Carreyrou gives a lot of credit to the author for giving the tip that turned Carreyrou's interest toward Theranos. Strangely, there's not mention of why the blog suddenly shut down. If you google around, you'll see it closed up a few weeks after Carreyrou's first big Theranos story.
[1] edit: via a comment on the oldest HN post (Sept. 2013) about Theranos, I found a link an online summary of the patent dispute: