Actually there is a blood test to see if you're allergic to a specific protein that's indicative of celiac disease. No need to go back on gluten for a biopsy. If the blood test comes back negative and you're not allergic to that specific protein, that does not mean that gluten is not a problem for you. It could mean that foods high in FODMAPS is the culprit. If I remember correctly - and you can look this up on Wikipedia - FODMAPS are basically fermentable carbohydrates. Wheat, rye and barley are the highest in FODMAPS and the highest in gluten. Unfortunately, FODMAPS are found in other foods (fruits, vegetables, legumes, etc), too, but not as much as wheat. So, if you're still having some intestinal and other issues, the FODMAPS could be the culprit.

I went off gluten several years ago due to intestinal issues and immediately felt better. The cystic acne cleared up. I still get cysts every now and then, but they are rare