I am antibody negative but my SFEMG came out abnormal. I am confident in my MG diagnosis. Are you on anything but Mestinon? Maybe it is time to try cellcept? My Mg has been progressive. It seems that about every 6 months, I take a significant step down and there is no going back. I am having a flare now. I was on 2000 cellcept and 540 of mestinon a day and 10 prednisone every other day. They had to up the pregnisone back to 20 a day and 660 of mestinon and do IVIG for the symptoms to subside again. There are other treatment option they may consider after your testing.

I hate prednisone and the side effects but it does give me a quick fix.

good luck
kathie