--the GAD65 antibody has been found, unfortunately, to not be that specific a test.

Originally, clinicians were using it to test for susceptibility to Type I autoimmune diabetes, as it was an antibody with action against pancreatic islet cells. (I know I've had the test done by endocrinologists in the past with that reasoning.) But it has been found that there is a second, related islet cell antibody that is more predictive of that (IA-2) but not as commonly manifested. So, when autoimmune diabetes is suspected--and it can happen in older people, not just "juveniles"--autoantibodies to insulin are tested, as well, and of course blood sugar and insulin levels are closely monitored.

But these antibodies can be found, at somewhat lower rates (so, not as specifically), in a number of neuroendocrine disorders, from thyroditis to pernicious anemia to even sometimes Myesthenia Gravis or Lambert-Eaton syndrome or other dysautonomias. GAD 65 is generally seen at higher levels, if present at all, in patients with autoimmune encephalitis, myelitis, and stiff-man syndrome, than in people with neuroendocrine disorders.

The interpretation of all this is complex, though the Mayo Clinic site is pretty comprehensive:

GD65S - Clinical: Glutamic Acid Decarboxylase (GAD65) Antibody Assay, Serum

What were your titres?

And,yes, it is good to hear from you again, despite this.