My two and a half-year-old daughter has had sweet, fruity breath for a long time, since she as much younger. I recently tested her glucose level at home with a prick test. Her random test level, three hours after a meal was 107 mg/dl (5.9 mmol/L) and her fasting level was 97 mg/dl 5.4 mmol/L]. She has no other symptoms at all, is normal height and weight. She is active and happy. Could this be diabetes?

This does not sound like diabetes with normal blood glucose levels. I assume also urine testing for sugar also was negative. Symptoms in a preschool-aged child would usually be excess urination, excess thirst, unexplained weight loss and/or bedwetting. But fruity sweet odor could be from excess body ketones being excreted through lungs. This could occur with high sugar levels like in diabetes, of course, but your testing suggests this is not diabetes. So, I would go back to your regular child’s doctor and ask for ketone testing to be done. Easiest to do on a urine test but also can be done on blood testing as well. Inadequate food intake/calories would be an important thing to review with your pediatrician since this would also cause ketones in the blood/urine and then be discernible in breath. There are several more rare explanations that also would need to be considered as well.