I was dx'd by clinical observation and strength testing. MG was suspected.

So they gave me 60mg Mestinon and a PA waited 30 min in the exam room monitoring my eyelids and corners of mouth every 5 min.

Finally neuro came back in - repeated the observations (mostly eyelids and smile), then repeated the strength tests......and voila! I had a dx.

Only then did they order the blood work and the SFEMG - both of which showed nothing!

My neuro also said that someone without MG can not handle Mestinon (unless they have had a recent and serious exposure to insecticide or nerve gas).