there are several tests used
A1c your average BG (blood Sugar) for the last 90 days. since it is an averaging test you can have problems that the test wont show IE reactive hypoglycemia.
Fasting BG A fasting BG test your fasting BG. A persons fasting BG is usually the last thing to go bad, you can have reactive hypoglycemia or High PP (Post postprandial numbers (after eating)) and still have good Fasting BG.
OGTT Oral Glucose Tolerance Test If doen correctly you drink 200 of glucose then measure your BG every 15 or 20 minutes for 3 hours. This will tell you how well your body reacts to glucose. The Test will tell you if you have Reactive hypoglycemia and or high PP, it will tell you how your phase 1 insulin response is. as well as your phase 2.
let me repeat on the OGTT MEASURE YOUR BG EVERY 15 OR 20 MINUTES measuring only once will ONLY give you your PP test results.
You've had 3 doctors say the same thing (using different words). The most informative way of saying it was that you're pre-diabetic (a red flag which should be interpreted as something you can address now if you choose, and before it becomes testing within the range of officially having diabetes).
Your fasting urine sugar content is often the classic test result that really grabs a doctor's attention and I think that value carries the most weight. To you know your test result and how close it is the outside of the normal range? (usually that's clearly stated beside your test result on lab test reports, and often circled or marked when a result is outside the normally healthy range). There are also tests less commonly used, such as how well your adrenal glands can handle supervised glucose consumption.
Often dodging the bullet comes down to the early choice (better sooner than later) of losing a few pounds through healthier food choices and quantities, being more active (not exercise necessarily at all, merely less sedentary -- lots more walking than riding/driving, stairs instead of elevators, standing replacing some of your sitting time, seeking out bits of activity rather than avoiding it, that sort of thing).