I am doing a project on obese children and adolescents, screening them for hyperinsulinemia. I do fasting blood glucose and insulin levels. Is there any role for glycosylated hemoglobin levels?

The measurements which you include will depend both on your research objective and your resources. Obesity can easily and inexpensively be defined in terms of Body Mass Index, insulin levels either fasting or better still at 3 minutes after a precise intravenous glucose load is a gauge of insulin resistance However, it seems to me that you also want to have a measure of actual glucose intolerance. Here you have a choice between a fasting blood glucose which is accurate, inexpensive and widely acknowledged and glycosylated haemoglobin which is more expensive and rather less reliable, but which also reflects a longer time frame. Ideally, you should do both.

DOB