If you test positive on an IgG test for yeast, then you need to avoid consuming yeasts, foods rich in yeast like fermented foods, and fungi like mold,(cheeses,) and mushrooms.
The Prometheus tests include IgG and IgA sensitivities to yeast and IgG sensitivity to the flagellum of a bacteria. There is a relationship between having these sensitivities and a person's likelihood of having Crohn's and possibly intestinal permeability.
IgG sensitivity is an allergic reaction that takes place over a few hours or days rather than instantly, like happens with the kind of allergic reaction most people are familiar with. If you are IgG positive for yeast and eat some, you may not react right away so it is hard to tell what is causing the problem. In my case eating yeast made me gassy and bloated, plus gave me other IBS symptoms like D and having to go to the bathroom all day long. My whole day was about
farting and pooping
I feel so much better since having an ELISA test, (which in my case identified IgG antibodies in a few foods including yeasts), and cutting out those foods.
Most drs, even GI's don't seem to know about
or be on board with testing for IgG antibodies. You can ask a naturopath for an IgG test, US Biotek is a reputable lab that makes test kits that include tests for many foods. Wishing you the best!