What they promised is theoretically possible, but they ran afoul of the huge practical problems that made people with actual biology and engineering backgrounds (like myself) very, very skeptical.
it's not theoretically possible, due to the statistics of small numbers. You can resolve the nanotainer problem by collecting many of them, but by the time you can measure a statistical difference, you might as well have collected a large volume of blood in the first place.
I agree that analyzing small volumes of blood is theoretically possible , but afaik it's yet unclear that you can get good samples from blood drawn from fingers, because it's mixed with interstitial fluid.