Mewonders why Google is developing this. Sure, Google is pretty diverse, but medical technology still seems a bit out-of-scope.

Questions of corporate motivation aside, however, this will never replace the majority of blood draws. The patent claims it is only intended for small samples, so if the lab needs more than this device can reliably extract in one go, they'll do it the old-fashioned way. Additionally, there's a high likelihood of hemolysis (rupturing of red blood cells, which releases haemoglobin and the rest of the contents of the cytoplasm into the blood plasma). The patent does not appear to address that issue (perhaps I just missed it, but I saw no references), but my wife (who is an ICU/ER nurse) tells me it is problem. That also severely restricts the range of tests for which blood drawn by this method would be suitable.