The reason Theranos was always a fraud is it is well known (as in for decades) that you can’t get reliable sampling from a finger prick sample even with a perfect detector.

The reason why is that the blood from a finger prick is a random mixture of veinous and arterial blood with a variable amount of cell debris and contamination from what is on the skin. Not even Kissinger (sorry I mean Lucifer) could give you an accurate diagnosis based on finger prick.