I hate to tell a doctor that he is wrong. But he is wrong. Steroids, in a low, medium, or high dose, all affect the outward signs of MG (or other autoimmune diseases). They affect antibody tests and EMGs. There are some people on steroids who have high antibodies no matter what. There are some people who have a positive SFEMG even without symptoms!
The one thing about this stupid disease is that there is a spectrum of how it presents and how it tests. I know that doctors like their algorithms. How nice would that be if we all fit them?
I don't have the energy to put up any articles (this summer is doing a number on me). But the science of this is sound.
Are you on steroids now? If not, they should redo the MuSK—if your insurance will allow that. MuSK patients are just different than AChR ones. It is very important to know which one you have!
I had a negative AChR test and then a positive one. There are both circulating and tissue bound (those busy attacking tissues) antibodies. This has MuSK listed, even though the descriptor says drug-induced MG!
Drug-induced MG
Here you go. Look under "cautions" in this Mayo site!!!
MUSK - Clinical: Muscle-Specific Kinase (MuSK) Autoantibody, Serum
This is just an interesting description of the different AChR antibodies and how they behave.
Acetylcholine Receptor (AChR) Antibody: The Test
I hope that helps!
Annie