Despite that a specialist diagnosed me with ME/CFS, my charts say "primary immunodeficiency: IgA deficiency" because that's what my immunologist chose. He couldn't see putting "chronic fatigue" down because he knows what's up.
I suspect a very small fraction will ever potentially see an immunologist before diagnosis.
My understanding is that IgA deficiency is not usual amongst patients with CFS.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC120010/ (a 2002 review)
(iii) IgA.
One study reported decreases in IgA (
58) but attributed this to abnormally high control values consistent with their being no difference in IgA. Four other studies found this variable to be normal
Having an 'unusual' diagnosis may not actually help at all.
If you are seeking help from whatever source, on the basis of an illness, and your presentation is atypical, because you 'really' have CFS, and your diagnostic label is a symptom of that I'm unsure how it helps.
Sure - in the case where the diagnosing physician or practice knows your actual condition and what would help or hurt - great.
But that can happen with CFS too.