I am seeing a competent immunological expert who is up on the latest research and have greatly benefited from lab testing, which has informed my treatment, and which is helping.
What was NOT helpful was the parade of MDs who took my money and refused to do testing and suggested CBT and GET. It delayed my getting proper treatment by a year.
We don't know all the answers. No one does.
There seem to be a number of different interpretations of the same labs by noted CFS experts with published work.
As a patient, I find it far more helpful to have lab testing that shows something and then see what the doctors will do with it.
On my journey, I've been amazed at hearing remarkable, brilliant doctors having the humility to say "I don't know" or "We were taught this in medical school, but now we've learned that..." or "this new research has really changed our view of" or "I used to practice this way, but then I learned..." or "it works that way for many patients, but your situation is different and surprising because..." I've been far less impressed by doctors who are dogmatic, stick to narrow and static viewpoints, treat me like a moron, and think they know all the answers - they simply don't.
From my experience, I not only have the titers on the labs but also have other symptoms and labs suggesting that the titers are actually valid. I doubted them for a long time, due to listening to folks with your viewpoint, but having now seen multiple very competent doctors saying the same things as I'd read elsewhere on my own, I tend to believe them.
It sure beats psychotherapy as an answer due to a lack of data to base decisions on.