My 16 year old daughter, who weighs 275 pounds, had an insulin level of 47, but I have no idea what that means. We have a family history of diabetes on both sides. Is this a sign of diabetes?

With a body weight of 275 pounds at age16, your daughter is very significantly overweight, and as such is most certainly vulnerable to type 2 diabetes. Her serum insulin at 47 is right at the upper end of the normal fasting range if it is expressed in microunits/ml, but you need to check this with her doctor. It would seem to confirm a measure of insulin resistance which would also be consistent with type 2 diabetes.

You don’t say what her fasting blood sugar level was at the time of the insulin sample, but it would not surprise me if it was greater than 125 mg/dl [6.9 mmol/L] or if a random blood sugar was greater than 200 mg/dl [11.1 mmol/L]. Both values might offer confirmatory evidence as to whether or not your daughter has clinically evident diabetes at this time. It is important to find out as soon as possible, but even if she still has normal glucose tolerance, she really does need to begin on a guided weight loss program as soon as possible.

DOB