The Theranos folks discussed some results using the mini-lab vs Siemens equipment during a presentation to the AACC: [1]
My understanding is that their ability to perform some tests, and to do it accurately was real, such as their FDA approved herpes test. However the number of tests they could perform on a single sample (primarily due to volume?) was drastically lower than they claimed. They were also found to be diluting samples, and had poor lab practices in a number of instances: [2] [3] [4]
When dealing with people's health there is no room for inaccuracy as other's lives and well-fare potentially hang in the balance.