Note there are other kinds of primary immune deficiencies besides common variable. It's not enough to just look at IGG levels. A complete assessment involves looking at whether you are producing antibodies after you get vaccinated (i.e. if you get a vaccine and your titers don't go up, that's proof of a problem even if your IGG levels are normal). Also, absence of certain lymphocyte subsets is an immune deficiency. For example, natural killer cell deficiency is it's own disorder. The chief symptom is recurrent herpesvirus infections. Also, this is not common, but some patients with "CFS" symptoms have turned out to have chromosomally integrated HHV-6. This means that they were unlucky enough to be born with the virus integrated into their genes. These patients have very high levels of HHV-6 on PCR and need the most powerful antivirals, but they can be treated. Peterson, Kogelnik, and Montoya have run into this subset occasionally. Just because a patient meets the CFS criteria is no reason to give up looking for other causes. If your diagnosis is not helping you, find someone who is open to challenging it.