I have written you a couple of times about my daughter. Her endocrinologist said all the laboratory work was normal, but didn’t really provide any explanation of what was done. I got her results in the mail yesterday and was wondering if you could explain these results to me: GAD–less than 1; Insulin–7.2; and C-Peptide–1.3. I know they said these fall within the normal ranges but, what are the normal ranges?

You really need to discuss this with your doctor since a lot would depend upon which laboratory was utilized and exactly what they were looking for. In general, C-Peptide tells one about how much insulin the pancreas beta cells are still producing, so the higher the number, the more insulin is being made. GAD is a type of antibody that, if positive, indicates beta cell autoimmunity occurring. So, with a positive GAD, the higher the number, the more antibody; this indicates type 1 autoimmune diabetes rather than type 2. I cannot tell about what you have listed as insulin. This could be an insulin level and would then only be useful if no insulin treatment were being given. It is mostly used in comparison with simultaneous blood glucose levels. It could also be an insulin antibody and then would be similar to GAD antibody. The third common antibody tested is ICA, islet cell antibody, and is also indicative of beta cell autoimmunity ongoing.

SB