For most blood assays, there is no such thing as a positive or negative. The normal range for cholesterol, for instance, has both an upper or lower limit. This

For most blood assays, there is no such thing as a positive or negative. The normal range for cholesterol, for instance, has both an upper or lower limit. This leads me to believe that the Theranos tests are just less precise overall, which makes it hard to justify their value even at an 80% discount.