The Mayo clinic is an excellent place for diagnostics. I was diagnosed with an autoimmune disease by my neurologist in my local area . however I was reffered to the Mayo Clinic for treatment. There my original diagnosis was checked by the neurologists in Rochester and I was also treated up there. The quickest way is to go to a doctor and get a referal to the Mayo Clinic. You can also try to make an appointment online, however getting a referal is a lot quicker.