I get that but I think it's unfortunate. Example: Labs for EBV can show up as a "past" infection and therefore Dr's don't believe that the virus is causing present symptoms while I very much think it still is. I think the virus can hide in organs, glands and CNS and not be show up on labs as an active infection.
I'm pretty sure that none of my regular doctors over the years (the ones who aren't specialists in ME/CFS) would have prescribed Valcyte for me. Seeing a specialist is unfortunately difficult and expensive, but it's how I've gotten treated.
My blood tests don't show evidence of
new herpes infections. But it's universally accepted that old herpes infections stay in our cells and reactivate from time to time, and (I think) that's what Valcyte fights. Ron Davis reports that there's no sign that ME/CFS patients have more herpes viruses than other people do -- and his associates have searched for them very carefully. So I believe that the immune systems of many people with ME/CFS overreact to even small reactivations of herpes infections.
By the way, I also believe that our immune systems overreact to many other kinds of infection, to physical stress from exercise, and to emotional stress -- the more we eliminate these things, the healthier we feel.