Sometimes, when blood sugars get out of whack, it can be pretty difficult to determine what's causing the problem. Diabetes is affected by so many variables: carbohydrates, fat, protein, exercise, illness, insulin activity. Then, you add the use of a delicate machine like an insulin pump, and you have to consider whether your insulin is still effective, whether your site has gotten clogged, or your site absorption is hindered.

Often, the reason for a high or low is obvious, like when it's...