glucose test question

So I can't remember if you can eat before the glucose test. This OB office does it different then my last. At my last office I got the drink to take home and an instruction sheet for my last 2 babies. With this baby I'm in a new state so new doc and you get the drink in the office and there were no instructions. It just clicked that my appt is the first of the morning and they are already closed for the day so I can't call and ask. Does anyone know? Lol