Mike, I could find absolutely no findings on that. Perhaps Mrs. D. might know more.

MG is a clinical diagnosis that is confirmed with testing. So if someone has all the obvious signs of fatigable weakness plus positive test results, chances are that they have MG.

Yes, some Acetylcholine Receptor Antibodies are positive (false or not) in ALS, in older patients, in some patients with Downs Syndrome, patients taking D-Penicillamine, etc. That is why a good doctor will take the sum of all the evidence before declaring someone has MG.

The three antibodies - binding, modulating and blocking - are not necessarily positive in all MG patients. Some only have binding, some only modulating and some have both.

http://neuromuscular.wustl.edu/mtime/mgdx.html

Antibody titers vary greatly, even for one person. It depends upon what meds you are on, how bad the MG is, etc. Even then, some patients who have severe MG, for example, may have a low titer while someone who is mild may have a high one. MG experts do not go by a ACh antibody test to decide how an MG patient is doing because it's highly variable. A clinical exam, breathing tests and various other tests like arterial blood gases is how a doctor determines how a patient is doing.

Is there a reason you are asking?

Annie