how do doctors test for low blood Sugar?im 14 and i get relay dizzy and my vision starts to go in and out and i get relay bad head aches so i mad an appointment to go to the doctors to get test for low blood suger and i was wondering how do they test for low blood Sugar please be Exacttt i want to know and if you not going to be nice then dont answerss my question and dontt say Idk or something stupid like that.