I would like to have a deeper look concerning reactivated virus infections which hasn't been done systematically in the past. As far as I've read, CFS specialists (like Lerner, Montoya, etc.) use mainly the IgG response to distuingish between reactivated or past infection. They say "high" titers suggest a reactivated infection. The problem is that they recommend either specialised labs in the US (Labcorp, etc.) or specific manufacturer testkits (like Diasorin) on which their interpretation guidlines focus. In Germany, the labs don't tell me, which manufacturer testkit they use. So I'm not sure what to do now. If I let the herpes family test in a normal lab, it will surely come back IgM negative and IgG positive, and then I don't know if this IgG is high or not in my case (the labs will of course say it's just normal and I don't know a CFS doctor here). So what would you recommend me? I can give you two examples. I tested for Varicella zoster a few years ago. It came back IgM negativ (normal < 22 U) and IgG positve with 2053 U (normal < 22 U). The lab says it's just fine. I don't know what to do with the results I got tested in another lab for parvovirus B19: IgM negative, IgG 150 U (normal < 3 U). The lab doc says: remote infection. Then I asked him and said that the antibodies seems quite high for me. He said that's true, but it had no consequences. If I don't know how to interpret the results, the tests are not helpful for me.