My five-year-old daughter has type 1, diagnosed at age three. My younger child, currently age three, has participated in the TrialNet study to find out if she were at risk to develop type 1 as well. At the time she participated (one year ago), she tested negative. The people involved with the study told us to re-test her every year because a negative status can change. I was wondering if you have any information on how often this happens, and what her risk would be of eventually developing type 1, despite a negative test history.

Antibody testing to find out who is at risk is helpful if positive but less helpful if negative. The reason is that someone can go from negative to positive and we do not really understand how often this occurs. But, we suspect that there are many children and adults who start out antibody negative and then something “exposes” them, the immune system responds and the antibody levels change. If gene testing was also done then, if identical genes, this would pose higher risks for antibody conversion and eventual diabetes than if the gene tests were dissimilar. So, we usually recommend retesting just as the TrialNet folks have advised about every one to two years. It is reassuring if remaining negative, of course; more worrisome if there is a change and then it depends upon whether one or more than one antibody changes and how high the antibody titers are, if and when they change. You may want to discuss this with the TrialNet folks in more detail since they have more specific information about the previous results.

SB