Like "What are you eating? What one eats has a lot to do with how our Blood Glucose (BG) levels are. Also are you taking any medications like prednisone pills or cortisosteroid shots. There are others which raise one's BG levels but I don't remember where to find that list. EDIT: My 2nd wife had BGs in the 600s a couple of times (her meter just said "Hi") and we were instructed by the nurse on call to go to the ER. They put her on a continuing insulin drip and they watched her BGs for about 4 hrs while it came down closer to normal. 600 + is dangerous territory to be in. I would recommend going to the ER ASAP when it gets that high! "