Annie, The short answer is "yes," they do change.

Someone can get an autoimmune disease slowly or quickly or anywhere in between. The more severe cases of MG have high antibody titers and may be clinically severe right away. Ocular only MG patients may not have a positive antibody test right away. It is highly variable.

Here are some articles for you to read:

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1028609/

http://www.mayomedicallaboratories.c...erpretive/8338

http://www.cmj.org/periodical/PaperL...17581751205552

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

Do you have the actual lab sheet from Mayo? I'm asking because they DO NOT only do the AChR binding test. It is always done along with the AChR modulating test. The AChR panel has binding, modulating and blocking. Blocking is not always done. If the MuSK had already been done, I doubt they would redo it at Mayo. There is only one lab in the country who has "permission" to do the MuSK test so far (they have proprietary rights). So Mayo would've had to send the blood out to be checked.

You can have your internist redo the AChR antibody panel and send it off to Mayo. Any doctor can order that test.

You can always get a 2nd opinion from another internist or neuro. It can be helpful but it can hurt too. Patients who see too many specialists can be seen as "doctor shoppers" or "doctor hoppers" that want a doctor to confirm something that doesn't really exist. And, no, I'm not saying that is the case with you! I'm simply pointing out how doctors think about this stuff.

I hope you can get some answers as to what is going on.