Terri, I'm sorry, I don't know how to test G levels, but there must be some way to because I have a video that talks about it indirectly. I would check on the Internet or with your doctor. I'm sorry to hear about this situation but fortunately, I believe there is hope, and this is one of the great things about the Internet: You can see what others are doing and what kind of success they are having with various treatments. I have personally been told by some parents with autistic children that they put their children on diets to avoid certain foods and/or took mercury chelation and have had tremendous success. If you're not already, you may want to search Yahoo for some groups related to this subject and see what the most successful treatments are.