I am very confused and was hoping someone could help. We think my son (age 10) has PANDAS. He has tics, obtrusive thoughts, self-harming behaviors, extreme mood swings and separation anxiety that came on very suddenly in the winter. Prior to this, he was a calm, social, happy guy. He also had a severe case of impetigo in the winter so we thought that could have been the trigger. We brought it up with our pediatrician who took an ASO Titer test that came back normal. I had read that this didn't rule out PANDAS, but she wasn't willing to pursue it so we found a ND who is a specialist in PANDAS who agreed it could be PANDAS. She did blood work and the cultures came back showing abnormal amount of strep in both his rectum and throat, but ASO titer, AntiDNAse-B titer came back negative. His immunoglobulin A is slightly low and he is Vit D deficient (but we live in a rainy place so by itself that's not abnormal). Our ND is theorizing that he has had strep for a while, but his immune system is depressed and not fighting it correctly (I guess by producing antibodies - I don't know) Also, I read that perianal strep doesn't usually cause elevated titers, so they are not helpful in diagnosis. However, his regular doctor (and also an ID DR that she consulted with) can't get past the fact that the titers aren't raised. She told me that everyone has strep in their body and that she doesn't interpret the labs as suggesting PANDAS. They also don't buy that his immune system is depressed because they don't feel his Immunoglobulin A is low enough to really indicate immune issues. Anyone have this issue - that all the titer tests come back normal, but the culture for Strep shows abnormal amounts. I'm wondering what the science is behind this - if the antibodies are the issue with PANDAS (because they attacking the brain instead of the strep), why are his antibodies not elevated? Thanks in advance!!