<i>Perhaps I just don&#x27;t understand the phobia that some people have around blood tests but it is my understanding that you get a blood test as a way to gauge your health, not because it makes you feel nice. The hold up doesn&#x27;t seem to be that tons of people are afraid of needles otherwise they would be getting tested all the time. The hold up to people getting blood tests all the time is that doctors don&#x27;t order them, presumably because doctors don&#x27;t think people need them. As long as the test isn&#x27;t extremely uncomfortable for the patient, I would think that accuracy is really the only measure of quality for a test and it seems to me that they are willing to sacrifice accuracy in favor of making people feel comfortable.</i><p>Couple of potential issues: one is that blood tests can be extremely expensive.  They are run by delicate, temperamental, and pricy analyzers that have to be babysat by reasonably well-trained personnel.  Some tests need costly reagents.  Still others aren&#x27;t readily automated at all and require a lot of manual inspection and interpretation, again by people who don&#x27;t work for free.  Meanwhile, doctors are under external pressure to keep costs down, sometimes to a fault.  I think these are the pain points that Theranos is trying to address.<p>The second issue is the real elephant in the room: statistics.  Accuracy is not a simple concept in this business.  If Theranos succeeds in commoditizing a large number of blood tests and making them available to people without medical supervision, there will be some unintended consequences.  I think these are positive goals -- don&#x27;t get me wrong -- but the fact is that the traditional medical priesthood is still going to be needed to follow up on the tests.  If you run enough lab tests on a sample of your own blood, you <i>will</i> get some positive results for diseases you don&#x27;t have.  A test that&#x27;s 99.9% accurate for say, HIV, is going to report a lot of false positives if you give the test to people who were never in a high-risk demographic to begin with.<p>So when a physician decides which tests should be ordered and which ones should be skipped, they aren&#x27;t just being financially stingy.  They&#x27;re also trying to get at the most likely diagnosis without wasting time on laboratory snipe hunts.  I don&#x27;t think anyone including Theranos can do much about this problem.  It&#x27;s just too hard to come up with a perfect medical test, let alone a perfect machine to execute it.