--that when I have my yearly glucose tolerance test, I make sure the order is written for FIVE hours, with glucose and insulin level drawings at baseline, a half-hour post drink consumption, 1 hour post, 1.5 hours post, 2 hours post, 2.5 hous post, and then at 3, 4, and 5 hours post.

I may be going a bit overboard--one may not need quite the length or number of draws that I insist on--but knowing as I do my insulin resistance and tendency towards reactive hypoglycemia, I do this so I can interpret the rises and falls of both the glucose level and the insulin reaction to it--the insulin reaction lags the glucose reaction--and to see if there is overreaction of the feedback system (which generally means too much insulin produced in response to glucose challenge, resulting in reactive hypoglycemia). I also want to see precisely when this happens, which is why I want half hour draws the first three hours.