LabCorp, you know, the place where you get blood drawn. This is the Tempe location, notable because it is open on Saturdays. On Saturdays, they open at 9am and EVERYONE wants to be first. Get there at 9:05 and the place will be packed.
The guy who took my blood was relaxed, friendly, and very good at what he was doing. If you don't mind a wait sometimes, this is a good place to go if you need labwork done.