What are your symptoms? Did they do any other test such as tensilon, ice test, or serum antibodies? If they do not think it is MG, did they say what they think it is? Did they do test for LEMS too?

Let us know. Several MGers here go to Mayo. They may be able to guide you better than me. What caused the doctors to originally diagnose you with MG? And where you on Mestinon when you were being tested or had just taken a dose of Mestinon before the single fiber EMG.

I hope our members can help guide you through this confusion.
kathie