I had to convert since most people in the US use mg/dl, but my highest was 43 (when I was diagnosed at 16, semi-conscious, rushed to the ER). My low was last night and my husband checked it because I had blacked out was less than 1 (my meter won’t read lower than 1 (18mg/dl) – it just displays “LOW”). Usually I can get lows down to 1.5 and still function enough to get sugar. Unfortunately this episode happened at night while sleeping.