I've never seen a $3000 blood test. A family member got an exceptionally rare blood test this summer though; I'll try and look through his paperwork, but I'd be shocked to hear even that test cost so much.
It is actually really difficult to find out how much stuff costs at a hospital. That is one of my main complaints about the healthcare system. It is wasteful because the hospital environment makes you forget that things cost money, and that some tests have a very low probability of doing anything other than costing you money (not saying that was the case with your family member, just in general).
Hospitals really mess with people's cost-benefit analysis, which isn't normally too good to begin with. I was with someone in the hospital a few months ago, and we got the strangest looks when we tried to find out how much a test would cost. Ultimately we decided not to do the test, which was a long shot to find anything for a problem that wasn't very serious, and save a bunch of money. I wish there were some way to inject some more rationality into healthcare to get around the mindset of always doing everything possible, no matter the costs and possible benefits of treatments or tests.
In this case the exceptionally rare blood test was actually the crux of solving a major, chronic condition. That wasn't obvious until after the fact though.
While I do understand your arguments about rationality, I'd also point out that the prices cited by hospitals have very little relationship to reality and costs. Quite a few tests become far more rational when looking at cost rather than price.
(Not intended as an argument for any particular structure of healthcare, just an observation.)
