I was diagnosed with myasthenia gravis in July, 2005 based on clinical diagnosis with good results from taking Mestinon. Over the past two years, my symptoms have worsened (but I also have had a very demanding full time job during this time which is too much for me). I presently take 60 mg Mestinon (3 to 4 times per day) plus sustained release at night. I also have IVIG treatments once every three weeks. I tried Prednisone (40 mg/day) for a month (it was a great benefit) but put on 50 pounds and had high blood pressure so my neurologist took me off it. The IVIG helps alot. I still struggle much and the past year have developed shortness of breath when tired. I went to academic hospital for EMG testing for a second opinion. They had me go off Mestinon for two days. When I did this, my symptoms escalated and I was very weak, although I was feeling well before I went off the Mestinon due to IVIG treatment 5 days before. The EMG test was negative which the doctor there was very surprised about. He said before the test that the exam indicated mg. After I left, I went back on the Mestinon and felt much better. Could the IVIG treatment interfere with the EMG test? How can the Mestinon work and the test be negative - that is my main question? I am seronegative as well. I am so confused now. My neurologist here at home dismissed the negative results. But the doctor who gave the test is not convinced I have mg due to the negative results and wants me to return in two months.