I also had an OGTT, 2 months after discontinuing every medication. I quit exercise for 2 days, and had normal food as always. For the test, I dissolved 75 gm dextrose monohydrate in water and drank it. The blood glucose readings were:
30 min 225!
1 hr 171
Had to go out. The next was checked in a lab.
2 hr 12 min 91
My peak was very high, but then the insulin kicked in and in about two hours, my blood glucose returned to fasting levels. According to WHO criteria, this is considered non-diabetic.