First of all, I want to offer you a cyber hug - I read your earlier posts on the pandas forum. I didn't have a chance to read the above responses - but was wondering if your insurance will cover any of it. I'm fortunate, where our insurance covers most of the Igenex cost. If not, you might want to consider putting the expense towards an llmd visit instead. Are you close to Dr. J? If I remember correctly your child was + (or IND) on band 83-93. Dr. J feels band 83 is HIGHLY suggestive of Bb. Before our appt. with Dr. J I ran the Igenex lyme western blot test with our ped (positive) and when I was still skeptical - ran the band 31 epitope (negative). When we finally went to see Dr. J, he said it was a waste of money to run the epitope because band 83-93 is very suggestive of lyme. He went on to find Bartonella & Rickettsia. But it comes down to your decision.
We were in a similar place as you are now - a PANDAS diagnosis, and antibiotics not helping enough, ready to consider immune modulating treatments. I wasn't sold on lyme, but searching for answers and considering it. I was especially worried about an LLMD, because our experience with EVERY doctor we've seen has been that they see things through their specialty. DS has been misdiagnosed with so many things. I didn't want to fall into that trap again. And his Lyme WB came back negative, so I was ready to move on. But one of the moms here encouraged me to test myself incase my kids have congenital lyme. I was willing to try just about anything before IVIG. So I guess I'm lucky that MY lyme test came back CDC positive, so there was no room for doubt. We practically ran to the nearest LLMD, which is a 12 hour drive into the U.S. Ugh. Please see my post from 2 days ago "Seeing Amazing Progress". We are truly seeing amazing progress in PANDAS DS! We retested through IGeneX and he's IGeneX positive, but not CDC positive. All 3 of my kids are positive via IGeneX.
Our LLMD only asked us for the lyme western blot IgG and IgM, which it sounds like you've already done. INDs (which is a very weak positive in my opinion) on lyme specific bands and some positives sure sounds like a good reason to visit an LLMD, no matter how far away they are. Have you tried contacting ILADS to see if there's an LLMD closer to you? The LLMD would be the best person to suggest which tests, so you don't waste money ordering ones that aren't worth while. As far as antibiotics affecting results, you can contact IGeneX directly and they can give you that information. I know for the WB it doesn't matter.