June 29, 1999
Question from Pennsylvania, USA:
My 5 year old son was diagnosed with Type 1 diabetes at age 2. He was recently screened for celiac disease, and one test was "undetectable" while the other was "borderline positive." His endocrinologist has decided to retest in six months. I would like to know what the "AGG & AGI" tests are, and if one is of greater importance than the other.
I am not familiar with the terms AGG and AGI in relation to celiac disease; but the earlier test was for antiendomyseal antibody and it has been largely superceded in the last year or so by one for antitransglutaminase antibody. The latter test is not a significantly better discriminant; but it is much easier to carry out precisely. There is a wide variation in how various centers respond to a positive test. Some centers don’t test at all unless there is evidence of sensitivity to wheat protein or weight loss or inexplicable poor control. Others will screen automatically in all new onset Type 1A (autoimmune) diabetics and if the test is positive confirm it with a small bowel biopsy and initiate treatment. There are reasons for the more invasive approach that you may want to discuss with the doctor; but most centers now tend to screen for the Autoimmune Polyglandular Syndrome; but not to biopsy or treat unless there are specific clinical indications of celiac disease.