As I stated in that article, I'm actually not a huge fan of IgG food intolerance testing. I do use it occasionally with my patients, but it's never, ever one of the first things I do. This is partially because I have noticed that these tests tend to be very confusing and frustrating for the patient. Also, they tend to produce a high amount of false positives and false negatives, which is all the more frustrating for both doctor and patient.
To show why they can be confusing, I have provided an example of a test run through Genova Diagnostics below. Take a look at the dairy section- notice anything? They break diary down into seemingly random categories (some labs break dairy up even more). How can someone have a sensitivity to cheddar cheese but not cottage cheese? Or yogurt? Isn't it more likely that a patient with 1 or 2 red flags in this section has a casein or a whey sensitivity and should not eat any dairy?
This is why this type of testing is always a last-ditch effort in my office. I will only run this type of test once we have accounted for all the myriad of things that can skew the results. If we do all we can possibly do to clean up the gut and the patient still has symptoms, then and only then will I consider running this type of test.