Hi, Hankster. A lot of neurologists are willing to prescribe Mestinon (generic: pyridostigmine bromide) for people with only suspected MG. If it works, that's evidence (though not conclusive) of MG. If it doesn't, it doesn't mean too much, since many MG patients don't respond to Mestinon.

We have a lot of seronegative people here (blood tests negative) who are diagnosed with myasthenia gravis. It's quite common. I've seen statistics up to 20%, but I suspect the real number is much higher.

Many of us seronegatives (including me) were diagnosed by single fiber EMG. That's not a regular EMG. With a SFEMG, the doctor inserts a thin needle in the muscle and leaves it there while the patient slightly clenches the muscle and holds it (no shocks). It's considered very accurate for diagnosing MG, but not fool-proof.

There are three different antibodies that are commonly tested for with MG. The first is anti-AChR (acetylcholine receptor) antibodies. Patients with MG-like symptoms who test negative for this should be tested for anti-MuSK antibodies. The third possibility is Lambert-Eaton Syndrome (LEMS), which isn't MG, but which causes similar symptoms.

I hope you get answers soon. Please feel free to ask questions here. We would all be very happy to be able to help.

Abby