The diagram represents the basic process of: everything that needs to be done "error free" for a blood test result to be accurate and reliable in an Arizona DUI case. Each lab and jurisdiction may have variations of this process, but the general process is captured in the diagram.
As you can see the machine (a gas chromatograph) is just a small part of the process.
A reliable blood test result requires more than just the gas chromatograph to be working properly. Put another way, an accurate and reliable blood test result is loosely based on the following equation: Human + Machine = Accurate & Reliable Result.
However, the first two parts of the equation are not equally balanced. That is, they are not each 50% of the what is needed to get the right answer.
Despite the fact the gas chromatograph is only a small part of the process, it is common that the only records documenting, and verifying, the steps in the process were done error free concern the machine. The remaining majority of the process is usually left on unchecked and with limited documentation.