Prior to the beginning of the test have each student go to the bathroom to relieve themselves. Then every 2 hours a break should be given during which time the question is asked, "Does anyone need to go to the bathroom, it will be another 2 hours before you can go again?" If a student requests to go to the bathroom during the exam time, that should be allowed. But, be sure that the student understand that the time will not be made up, that student looses that exam time while they are gone. This should be fully explained prior to beginning the test just before the initial bathroom break is instigated. They should be instructed to thoroughly empty the bladder.
