Then they proceed with the OGTT/GTT sometimes 30 minutes, 1 hour, 2 hours and 3 hours after drinking the high glucose
drink. If you didn't fast the night before, your blood
sugars will be slightly elevated from the foods. The results will be a false positive.
As far as the meter, its hard to say without knowing the brand. I use a LifeScan OneTouch UltraMini. Every three months or so, I apply test fluid to a test strip to see if the readings fall between certain numbers.