My daughter has been having many episodes of low sugar (2.4-6.1 mmol/L [43-100 mg/dl]). We have been giving her lots of sweets and juice as she balks at fruit. We have an appointment with an endocrinologist and wonder what kind of test we should be prepared for.

You haven’t said how old your daughter is, but I am guessing that she’s a toddler. You also do not say that she has diabetes, and I am assuming that she does not. I am interested that you are measuring blood glucose on her. If she is genuinely hypoglycemic, then she should be being investigated now and not waiting for an outpatient appointment. However, she does need some tests.

I could not make a full list because of lack of information but would start with a full history of the problem and whether anyone else in the family has suffered (especially as a child). There are a number of inborn errors of metabolism that can show up like this which require specialised blood and urine tests to diagnose. Occasionally, a liver biopsy is necessary but not often. Timing of the hypos is also important. If they are all after prolonged fasting (e.g. overnight or before breakfast) then sometimes food in the late evening (e.g. cornstarch) solves the problem. The precise diagnosis will determine what is required in the way of treatment and whether the problem will go away.

KJR