As you say, there's no test, it's diagnosed by exclusion, so there's no metrics to check to assess compliance other than anecdotal response to symptoms. Conversely, I've not seen anything that says that NCGI can resolved or be cured either. This paper gives a good summation.
Basically, there's not much research period! That is changing though, I think there's research underway which could help give answers.
First, do you have celiac disease? Have you recently had a celiac antibodies follow-up blood test panel to see if gluten has been actually getting into your diet by accident or through cross contamination? If you haven't had the test, you should ask your doctor for one. You could also also ask for a follow-up endoscopy to see if you intestines have truly healed. This will rule out if gluten is really the problem.
If you don't have celiac, I assume you have Non-celiac gluten Intolerance because no one would stick to the gluten-free diet for six years unless you have had reductions in symptoms. There is no test for NCGI unfortunately. So, it is hard to say if gluten has been sneaking into your diet. You really are going to have to try to figure out if you are getting gluten into your diet.
If gluten is not the problem, then your doctor needs to check you for other issues, like SIBO.
There is a test to check for SIBO. Has this been done?
Once a celiac, always a celiac. There is no cure for celiac disease except to remain on a gluten free diet for life. I am not sure about NCGI. Not much research has been done. Maybe others can chime in?
I am so confused right now.... 6 years ago I went on gluten free diet... after being on it for the first yr I was 100%better up until 5 months ago in got the "flu" the doctors told me to cut out dairy sonic did and my diarrhea became better but not completely gone would not have it every day tho. I went to the gi doctor and they said to cut out fructose and dairy and keep gluten out... yesterday I went to the dietitian to see what I can eat and she gave me the list for fructose... she said it should have been on a antibiotic for sibo.... eventually I will be able to add dairy back and maybe gluten.... I said how can I add gluten back when this was my first problem... she goes well through fructose goes hand in hand with it... I said with gluten I vomit and am sick for weeks.... fructose isn't that bad I vomit sometimes but I'm not sick for weeks.... I'm just confused on really what is going on and was wondering if you or someone you know had sibo from gluten and or fructose and how Is this all related?
I see no one has responded to your query. Unfortunately I have yet to try making a pie crust. It was something I never mastered before going gluten free. Have you looked on Pinterest? You might find something there.