Hypoglycaemia is a term for low blood sugars. The normal blood sugar range is 4-6 mmol/L. When blood sugar levels are less than 3.0 mmol/L (which is about 55 mg/dl in different units), the nerves in the brain do not work well. There is no clear cut off sugar level that determines hypoglycaemia. It is likely that every child has a certain 'threshold' below which the brain is affected. Most doctors would investigate and treat children if the sugar drops below a level of 3.0 mmol/L.
