[hn_throwaway_99]

No, it's physically impossible. There is plenty of evidence that capillary blood simply isn't homogeneous enough in small volumes to do quantitative analysis.

But honestly, I actually don't think that's much of a big deal. The difference between taking a venous draw and doing a finger stick as not as big of a deal as Theranos made it out to be.

If instead Theranos had a small, portable analysis machine that could work with small volumes of venous blood, and they had a big deal with Walgreens to use that together with things like low, up-front pricing for tests, I think that still would have been a great advance. Note there are startups like Everlywell basically trying to make that vision (cheap, accessible, up-front pricing for medical tests) possible.