For people without diabetes, the fasting blood sugar (glucose) should be under 100 to be considered normal. If the fasting blood glucose is 100 to 125, you are considered to be at risk for developing diabetes. This is often called pre-diabetes.
If the fasting blood glucose is 126 or over, it is considered diabetes and should be rechecked on another day to confirm the diagnosis. When checking blood glucose levels for diagnosing diabetes, the test should always be done at a laboratory and not by using a home blood glucose meter.
For people with diabetes, the American Diabetes Association recommends a blood glucose level of between 70 and 130 whenever testing before a meal. If testing about 2 hours after a meal, the recommendation is that the blood glucose be under 180.