@sueinmn Thanks for all the info! This wouldn't be an at-home test. It involves a blood draw. My nurse practitioner suggested it. I do not have allergies since I don't have big reactions like hives to any food. Your answer, if I understand correctly, says the blood tests ordered by doctors (or NPs I suppose) are legit, and I did have such a test at a gastroenterologist office three years ago. But again, if I understand you correctly, the private companies marketing directly to individuals are offering tests that are short on evidence. The NP is recommending using the blood test from such a company.

I have done elimination diets before like the low FODMAP diet, alpha gal diet, low-acid diet, and the whole food diet. I am not a meticulous or patient person so in the end I go back to doing what I always do. I will have to buckle under and do a restrictive diet again while keeping a food journal and see what happens. So far whenever I did a restrictive diet before I didn't lose weight, which is a big goal of mine besides feeling better.