Bman,
I would say if you saw ANY improvement at all while on antibiotics, that's a pretty good indicator that it is PANDAS. Of course, if she did not clear it all the way, or if she has been exposed again (that's why you need to check EVERYONE), she will go back to square one. If she's positive, ask for a different antibiotic, and a stronger, longer course, and then take it from there. It's great that your doctor agreed to try the antibiotics, but if he's not willing to try something stronger, you need to get yourself a different doc! Our pediatrician did Amoxicillin the first time, and then when we went back and tested positive two weeks after finishing the antibiotics, they agreed to prescribe something different, although we had to ask and insist that this was not a new infection, but one that had not been taken care of by Amoxicillin.