Laura, I have not been able to find anything that constitutes a test for PAS, it is more made on the aggregation of several auto-immune conditions, usually with something like thyroid or diabetes as the primary one, though there does not seem to be a pattern or order in which these conditions develop. Or not as far as the things I could find would lead you to believe.

I also have somewhat elevated thyroid something or another that they are going to look at again in 6 months. Hmmm.

Looking into B12 deficiency is fascinating as it has neurological implications.
But also because of something in the gut that gets damaged, apparently auto-immune ....... leading to a loss of something called intrinsic factor....

Also because it can be underdiagnosed or missed for a long time, by which time neurological damage has occurred........ Another condition they have had treatments for for 60 years........