ugh, I am so sorry!! Yes, as Bipedal said - Dr's are just people, they do not know everything... in fact I have met a lot that don't know enough!
In my opinion - of course IVIG would affect your results - I had my repetitive stim 10 days after IVIG, and they said yes, my muscles are currently acting like they act on IVIG- which is almost normal.. therefore the tests will reflect how the muscles are acting at that time they are tested..Makes it hard when you cant really survive well without treatment, but still need to get tested...
I hope the rest of your visit goes better, good luck and keep us updated