Induced hyperglycemia is one way, along with a fasting glucose and glycated hemoglobin (HbA1c) test, to confirm a diagnosis of diabetes or prediabetes. Interpretation criteria vary somewhat from country to country and are regularly revised. The criteria in your report are from the Canadian Diabetes Association (2013 version, revised in 2016) and do not apply to pregnant women. A fasting glucose abnormality defined as a blood glucose level between 6.1 and 6.9 millimoles per litre (mmol/L) AFTER FASTING FOR AT LEAST 8 HOURS (no caloric intake) as well as the “glucose intolerance” category may be considered prediabetic states.
There are several conditions other than diabetes that can cause high fasting glucose levels: acromegaly (growth hormone-secreting pituitary tumour), acute stress, chronic kidney disease, overactive adrenal glands (Cushing’s disease), several medications, etc. Other conditions (gastric surgery, etc.) can also hinder interpretation of the test. The 2-hour glucose level must generally be higher than the fasting level. A fasting or 2-hour glucose level that is below normal could indicate a form of hypoglycemia.