My recent modulating antibodies were at 41, and on my test it showed that anything above 25 is positive. I'm not sure if the test you took has the same parameters as mine though. It also shows that anything less than 21 is negative. I've read that some people can be negative and have anti musk antibodies. Maybe you can mention that to your doctor.

Over the past ten years -- the first test was positive, the next neutral, and then negative, and now back to positive again.

Never had an IVIG before, so I don't know how that might affect your repetitive stimulation test.

I've given up looking for answers several times because doctors didn't want to dig deep enough, or they were ordering the wrong tests, but now my body is telling me that I have no choice but to get answers. I'm not sure what your symptoms are, but if your muscles are weak don't give up until you find an answer.