I think its because there are two different tests. The one hour Glucose Screen. Which doesnt really involve fasting. But a lot of places are different

I have to have the 2 hour Glucose Tolerance Test. I fast for 8 hours prior to the test, and can have heaps of water. This one determines how well your body deals with Glucose I think. You still go in have blood taken, drink stuff, then after an hour have blood taken, and then at 2 hours have blood taken. I think from what I remember. I know it involves 2 too many needles lol!