Can a fasting glucose rule out type 2 diabetes?

No, sir, a fasting blood glucose level within the 'normal' range can NOT rule out type 2 diabetes`. I say this as you could suffer with glucose intolerance, which means that when you eat your blood glucose level can easily rise into the diabetic range.

Ideally, your doctor should arrange for you to undergo an Oral Glucose Tolerance Test (OGTT). This is where you fast (not eat or drink) overnight, have your blood drawn to give a baseline on which further readings can be compared. You then drink a sickly sweet substance called glucola, then have blood drawn at hourly intervals. A comparison of these results would show how efficiently your pancreas is dealing with a sudden influx of glucose.

The HbA1c test, as suggested by amy lynn, WOULD give an average of your blood glucose levels over a 3 month period, but it would NOT be able to see rises in your blood glucose level after eating ... unless these rises lasted for a long time.

2

1

If you are in the very early stages of type 2 diabetes, it might be possible to have a fasting reading that is good one day but high the next day. It is possible for the earliest stages of type 2 diabetes to be missed in a fasting glucose test because the day of the test is a good reading. With single fasting tests, the food you ate the day before the test might have a minor impact on the test of the next day.

An A1C test is more accurate since it can read a three month average of how much sugar has been clinging to the blood cells. If you are convinced you might have a problem, then ask for an A1C test to get a more accurate check.